Glossary of Jewelry and Gemstones Terms

Glossary of Jewelry and Gemstones Terms

Jewelry consumers are often bombarded by technical, scientific and jewelry-trade phrases when shopping for that special piece of jewelry. Gemstone and jewelry terminology can sometimes sound like a foreign language altogether. Can you tell a baguette from a bezel? A cabochon from a crown? Or inclusion from a flaw?

Below are many of the words and phrases used when discussing gemstones and jewelries. It will allow you to better understand the lingo that so many sales associates speak, and next time you're at the store, you will sound like the expert.

A

Adularescence- The appearance of a floating, billowy light in cabochon gemstones or a stationary sheen on the flat surface of a gemstone. Seen in certain Feldspars such as Moonstone.

Altered Stone- Any stone that has been changed in appearance, particularly in color, by an artificial process. Also referred to as an Enhanced Gemstone or a Treated Gemstone. Heating, irradiation, and dyeing are among the treatment processes used to change gemstone appearance.

Amethystine- The color violet to purple in gemstones.

Angle of Incidence- The angle at which a ray of light enters a stone as measured from normal.

Angle of Reflection- The angle at which a reflected ray of light leaves a surface as measured from normal.

Angle of Refraction- The angle at which a reflected ray of light leaves a surface as measured from normal.

Anisotropic- Term used in gemology for double refraction.

Artificial Stone- A man-made, imitation or synthetic gem.

Asterism- The appearance of a rayed figure or rayed star in a gemstone, caused by the reflection of light from minute inclusions. Star Sapphires and Star Rubies are two well-known examples of gemstones featuring a rayed star.

Aventurescence- A glittery appearance of the surface of a gemstone, caused by the reflection of light off small mineral inclusions. Aventurine Quartz and Goldstone (glass) both have aventurescence.

B

Baguette setting- A rectangular-shaped stone with rows of step-like facets. If the baguette's two long sides taper inward, it is called a Tapered baguette. Baguettes in long, thin cut rectangles are often used as enhancements to a lager center stone, or on a watch bezel.

Balas Ruby- Trade name for Red Spinel.

Baroque- May apply to certain gemstones or pearls. Either a gemstone or pearl with an irregular shape, such as Tumbled Stones or Baroque Pearls.

Bar setting- Similar to the channel setting, it is a circular band of diamonds or gemstones that holds each stone in by a long thin bar, shared between two stones.

Barion cut- This has a traditional step-cut crown and a modified brilliant-cut pavilion. A square barion cut diamond has 61 facets, excluding the culet.

Base- The portion of a facetted gemstone below the Girdle. Also known as the Pavilion.

Baton- The English name for the Baguette cut.

Bead Setting- A method of securing a facetted stone. A small burr of metal is raised with a graver and worked to the edge of the stone. This burr is then burnished with a concave tipped punch into a small ball over the girdle of the stone. Normally used to secure very small gemstones, usually in multiples.

Bearding or girdle fringes- The outermost portion of the stone, called the girdle, can develop small cracks that resemble whiskers during the polishing process. The bearding can sometimes be removed, if not too dramatic, with slight re-polishing, and if the weight allows.

Bearing- The supporting ledge of a stone setting.

Bezel- With a bezel setting, a rim holds the stone and completely surrounds the gem. It is the upper portion above the girdle of a cut stone. Bezels can have straight edges, scalloped edges, or can be molded into any shape to accommodate the stone. A watch bezel is the upper part of the case surrounding the dial. They can be set with diamonds or other gemstones.

Biaxial- A double-refractive gemstone, which has two directions of single refraction or optic axes.

Birefringence- The numerical measurement of double refraction in gemstones.

Blemishes- The term blemish is used when the diamond has scratches or marks on the external area of the stone.

Blocking- The process of placing the facets on a stone.

Body Appearance- The optical characteristic of a gem produced by internal inclusions, fractures or layers.

Body Color- The dominant hue within a gemstone.

Box Setting- A method of stone setting in which the gem is enclosed in a box and the edges of the metal are pressed down to secure the stone.

Brilliance- Liveliness, or sparkle in a stone when light is reflected from the surface and from the total internal reflection of light.

Brilliancy- The total amount of white light returned to the viewer by a gem. This includes internal and external reflections.

Brilliant-cut- Brilliant cuts are scientifically found to reflect the most light from within the stone, and often are considered to have the most brilliance of all cuts. A round brilliant-cut diamond has 58 facets. Other brilliant cuts include the heart, oval, marquise and pear shaped.

Bristol Stone/Bristol Diamond- Old trade-term for colorless crystal quartz. Also a trade name for colored glass imitations, Bristol Glass or Bristows.

Bruting- A method of rough-diamond fashioning by rubbing one diamond against another.

C

Cabochon- A facet-less style of cutting that produces a smooth surface. They can be in many shapes, including round with high domes to squares.

Calibre Cut- Gemstones cut to a specific, standardized size for mounting. Also, small gem material cut for pave' setting.

Cameo- A gem or shell material--usually with two or more distinct colored layers. The top layer is carved in relief and the bottom layer acts as a contrasting background.

Carat- Unit of measure of weight of diamonds and gemstones. One carat is equivalent to 200 milligrams. One carat can also be divided into 100 "points." A .75-carat stone is the same as a 75-point or 3/4-carat stone.

Certification (or Diamond Grading Reports)- There are many recognized gemological laboratories that can grade your stones for a fee. The most well known is the GIA, Gemological Institute of America.

Change of Color- A phenomenon seen in some gems which have a different color in natural light than in artificial light. The color-change is caused by selective absorption and transmission of light. Alexandrite has become a very well known color-change gem, but other gemstones may exhibit the phenomenon.

Channel setting- Used most frequently for wedding and anniversary bands, a channel setting will set the stones right next to each other with no metal separating them.

Chatoyancy- The appearance of well-defined bands or threads of light across the surface of a gemstone. This appearance is caused by the reflection of light off small parallel mineral inclusions. May appear as a single-band chatoyancy--Cat's Eye--or a series of bands--Tiger's Eye.

Checking- The tendency of Opals to crack when exposed to heat or drying air. Also known as Crazing.

Chevee- A gemstone with a smooth concave depression.

Chip- A popular, common name for a small rose-cut or single-cut gemstone.

Clarity- A diamond often has natural imperfections, commonly referred to as inclusions, which contribute to its identifying characteristics. Inclusions are found within the diamond, and can be white, black, colorless, or even red or green. Most are undetectable by the human eye, and can only be seen with 10X magnification. Inclusions are ranked on a scale of perfection called clarity.

Claw Setting- A stone setting of projecting metal claws which grip the stone at--and just above--the girdle.

Clean- A trade term for gemstones which are free of noticeable flaws.

Cleavage- A natural area of the diamond where a weak bond holds the atoms together. The gem will be split along these planes by the cutter.

Cloud/Cloudy A group of small, white inclusions that give a cloudy appearance to a diamond.

Cluster setting- This setting surrounds a larger center stone with several smaller stones. It is designed to create a beautiful larger ring from many smaller stones.

Color- Diamonds are graded on a color scale established by the Gemological Institute of America (GIA). Fancy colors refer to diamonds with hues like pink, blue, green, yellow, and very rarely red. Fancy colors are not included in this color scale and are considered extremely rare. An example of this is the pink diamond.

Coated Stone- A gemstone covered by an artificially applied transparent material to enhance its color. Often used with Topaz.

Collet Set- A variation on box setting in which the sides of the box are filed away to sallow more light to enter the gemstone.

Color Zoning- Uneven color in gemstones in irregular patches. Can be either different colors or different tones of the same color.

Colored Stones- A gemstone other than a diamond.

Crazing- The tendency of Opals to crack when exposed to heat or drying air. Also known as Checking.

Critical Angle- Greatest angle measured from normal at which light can be refracted out of a stone. Small angle at which light is totally internally reflected.

Crown- This is the upper portion or the top of a diamond.

Crown Setting- A collet setting consisting off a flared cylinder with one end of the cylinder notched to form prongs.

Cryptocrystalline- Extremely small crystals which cannot be seen separately, even under high magnification.

Crystal- A solid made up of atoms, bounded by natural planar surfaces.

Crystal System- The classification of minerals according to the geometric form in which their crystals grow. Each mineral has a distinct system--Isometric, Tetragonal, Hexagonal, Orthorhombic, Monoclinic and Triclinic.

Crystalline- Having a regular crystal structure.

Crystallography- The science of the internal structure of crystals.

Cubic System- The Isometric crystal system which consists of three axes, each of equal length and perpendicular to others.

Culet- The bottom point of the diamond. It may be polished in some stones. Sometimes, a cutter may choose to make the culet a surface instead of a point.

Cushion cut- A mixed-cut diamond shaped like a square pillow.

Cut-  Cut refers to the angles and proportions a skilled craftsman creates in transforming a rough diamond into a polished diamond. Based on scientific formulas, a well-cut diamond will internally reflect light from one mirror-like facet to another and, disperse and reflect it through the top of the stone. This results in a display of brilliance and fire. Diamonds that are cut too deep or too shallow lose or leak light through the side or bottom, resulting in less brilliance, and ultimately value.

Cutting style- Cutting styles are different than diamond shapes. The simplest and most common way to explain cutting style is to categorize it into the following three basic types: Step-cut, Brilliant-cut and Mixed-cut.

Cuvette- A raised relief carved into a gemstone in a concave depression.

D

Deep cut- When a diamond is cut too deep, it will lose or leak light through the side or bottom. This results in less brilliance and value.

Density- Mass per unit volume. The amount of matter in a given space. The higher density/atomic mass of a gemstone, the more it weighs for a given size.

Dentelles- An early term for glass imitation stone without foil backing.

Diamond- A diamond is the hardest known natural substance. It is crystallized carbon. Diamonds are mined in their rough form and then, cut and polished to reveal their brilliance.

Diamond Grading Reports- There are many recognized gemological laboratories that can grade your diamond for a fee. The most well known is the GIA, Gemological Institute of America.

Dichroism- The transmission of two different colors in two different optical planes as light passes through a gemstone. Maybe used as a method of distinguishing one type of gemstone from another.

Dichroscope- An instrument used to view the light passing through a gemstone to determine the presence of dichroism.

Dispersion- When light enters a diamond it reflects off the facets and the angles cut into the stone. This distribution of light is known as dispersion, or the display of the spectral colors.

Dodecahedron- A twelve-sided geometric solid. One of the crystal forms found in the Isometric crystal system.

Double Refraction- The separation of a beam of light into two separate beams as it enters a gemstone. The two beams travel at different speeds. May be used to distinguish one gemstone material from another. Occurs in all crystal systems except Isometric.

Doublet- An assembled stone of two parts. Colorless cement or heat is used to join the parts together. Often used with Opals.

Durability- The combined characteristics of hardness, toughness and stability in gemstones. One of the deciding factors in gemstone value.

Dyed Stone- A gemstone to which an artificial stain is added to improve color or to imitate a more valuable gemstone.

E

Emerald shape- A rectangular or square-shaped cut-cornered diamond. A form of step cutting, this cut is favored for diamonds and emeralds, as well as many other stones, when the principle purpose is to enhance color rather than brilliancy. It is also sometimes used to emphasize the absence of color in diamonds.

F

Face- The plane surfaces which form the sides of a crystal.

Facet- Any flat polished surface of a diamond or gemstone. This style of cutting gives the stone many small faces at varying angles to one another. The placement, angle and shape of each facet are carefully planned and executed to show the stone's inherent beauty, fire, color, and brilliance to the fullest advantage.

Fancy Cut- A diamond cut other than round -- such as baguette, emerald, pear, marquise, square, oval, heart, etc.

Fancy Diamond- Any diamond with a body color strong enough to be attractive.

Fracture Filling- A process that injects a substance into a diamond to hide inclusions.

Feather- A type of inclusion or flaw within a diamond. It is described often as a small crack or fissure.

Fingerprint Inclusion- Liquid and/or gas or solid flaws in gemstones which align in the form of a human fingerprint.

Finish- Describes the exterior of the diamond. If a diamond is well polished, it has a very good finish.

Fire- Often a term used instead of "dispersion," it is the variety and intensity of rainbow colors seen when light is reflected from a diamond.

Flat-top setting- Like the Gypsy setting, this setting has a band that is one continuous piece that gets thicker at the top. A flat-top setting grows broader at the top so that a faceted stone can be inserted into the ring at the broadest part. The stone is held in place by metal chips attached at the stone's girdle.

Flaw- Any visible imperfection within a gemstone.

Fluorescence- When exposed to ultraviolet light, a diamond may exhibit a more whitish, yellowish or bluish tint, which may imply that the diamond has a property called fluorescence. The untrained eye can rarely see the effects of fluorescence. Diamond grading reports often state whether a diamond has fluorescent properties. Fluorescence is not considered a grading factor, only a characteristic of that particular diamond

Foil Backed- The adding of a layer of metallic foil to the back of a gemstone to improve its color or brilliancy.

Fracture- A break or chip in a gemstone in any direction other than along a cleavage plane.

G

Gemstone- A cut and polished stone which possesses the beauty, durability and rarity necessary for use in jewelry.

Gemology- The study of gemstones--identification, grading, appraisal, marketing, and fashioning.

Gemological Institute of America (GIA)- A nonprofit teaching institute considered the standard-bearer in the grading of diamonds and colored gemstones.

Geode- A rock which contains a cavity lined with quartz or other gemstone crystals.

Girasol- A gemstone with a glowing, milky sheen that moves as the stone is moved in the path of a light source.

Girdle- The outer edge of a cut stone, the dividing line between the crown and the pavilion. Sometimes the girdle is polished and sometimes it is unpolished. Ideally the width of the girdle should be even and proportional to the cut of the stone.

Glyptic- The art of engraving or carving gems.

Group- Two or more chemically related gemstone materials, similar in structure and physical properties.

Growth or grain lines- These can be considered internal flaws, and can often be seen only by rotating the diamond very slowly. They can appear and disappear almost instantaneously. They appear as small lines or planes within the diamond.

Gypsy setting- The Gypsy setting is predominantly used for men's jewelry. The band is one continuous piece that gets thicker at the top. The top is dome shaped and the stone is inserted in the middle.

H

Habit- The most common form in which a mineral occurs.

Hardness- Resistance a material offers to scratching or abrasion. Generally measured using the MOHS scale.

Head- An added finding to secure a gemstone in a prong setting.

Heat-Treatment- Heating a gemstone material to improve color.

Heavy Liquid- A liquid of known specific gravity, used to test the specific gravity of a gemstone.

Hexagonal System- A crystal system which consists of four axes, three intersect at a 60-degree angle of each other while the fourth is perpendicular to the other three.

Hollowed Cab- A cabochon hollowed from the back. Technique is sued to lighten the color of the stone.

I

Inclusion- "Internal characteristics" apparent to a trained or professional eye at 10x magnification. Inclusions can be bubbles, crystals, carbon spots, feathers, clouds, pinpoints, or other impurities, or even cracks and abrasions. They are what make a diamond so unique, as a fingerprint does for a person.

Illusion setting- This setting is more intricate than others in that it surrounds the stone to make it appear larger.

Intaglio- A design carved into the surface of a gemstone--the opposite in character of a cameo.

Intensity- The color of a gemstone from bright to dull.

Interference Colors- Colors revealed by a polarisope as polarized light pass through a gemstone. Used to detect the presence of double refractivity in a gemstone.

Iridescence- Spectral colors observed inside or on a gemstone. It is caused by light passing through layers of differing refractive indexes. The colors seen in Opals are a result of iridescence.

Isometric System- The Cubic crystal system which consists of three axes, each of equal length and perpendicular to others.

J

Jade- Called the stone of heaven, jade is a hard stone that has been treasured by the Chinese for over 7,000 years. Jade is actually a term that encompasses two different mineral species with similar appearance: nephrite and jadeite.

Jadeite- Jadeite is a sodium aluminum silicate and has become the most popular form of jade. It comes in a variety of colors, from popular greens to orange, yellow, brown, blue, purple, and black. On Mohs' scale of hardness, jadeite ranks 6.5 to 7 and it has a greasy luster. Primary jadeite sources include Burma (Myanmar), China, Japan, Canada, Guatemala, Kazakhstan, Russia (Siberia), and the United States (California).

Jasper- A fine-grained quartz, jasper is opaque and most commonly exhibits a brownish-red color, but it can also be green, yellow, brown, or black. On Mohs' scale of hardness, jasper ranks 6.5 to 7. Primary jasper sources include Egypt, Australia, Brazil, India, Canada, Kazakhstan, Madagascar, Russia, Uruguay, and the United States.

J-hoop- A J-hoop earring is a hoop earring that is not circular but elongated and curved on the bottom, resembling the letter J.

K

Karat- Karats are a unit of measure indicating the fineness of gold. Gold in its purest state is referred to as 24-karat gold. Most gold jewelry is actually made from a gold alloy containing gold and another metal or metals. Pure 24k gold is normally too soft for use in jewelry, so jewelers mix gold with another metal like nickel or silver to harden it, creating gold alloys of various purities: 10 karat gold is 41.7% pure gold; 12 karat gold is 50% pure gold; 14 karat gold is 58.3% pure gold and is ideal for jewelry because of its durability and affordability; 18 karat gold is 75% pure gold and is preferred in jewelry for its beauty and durability; and again, 24 karat is 100% pure gold and is therefore too soft for most jewelry.

Katzenberg Signature Collection- First debuting in December 2007 and exclusive to JTV, the Katzenberg Signature Collection is a very special selection of tanzanite gems fashioned with a high degree of expertise by Shlomo Katzenberg, world-renowned master lapidary with more than 30 years of hands-on experience. With a resume that includes fashioning gems for royalty and nobility in Europe and the Middle East, Mr. Katzenberg cuts each gem to obtain optimal symmetry and proportion to maximize each gem’s brilliance. Each finished gem is so expertly polished that it has a mirror-like surface and will arrive with a verification card stating that it was hand fashioned by Mr. Katzenberg.

Keshi pearl- The word Keshi comes from the Japanese for "poppy." It also refers to something being small and spontaneous. The term originated with Japanese Akoya pearl farmers when they found small "seed" pearls in the harvest that had not been nucleated. The “seed” pearls were actually a byproduct of the culturing process. However, Keshi pearls are still considered a cultured pearl even though they were not nucleated by man. South Sea culturing also produces a Keshi, as does the freshwater mollusk. Keshi pearls are typically small, but the south sea and freshwater variety can become quite large. Keshi pearls are almost always irregular in shape and always unique. A Keshi pearl strand is sure to be as unique as the woman it adorns.

Kianga™- Tanzanite Like a dazzling whirlwind of magnificent light, Kianga™ tanzanite captures the essence of tanzanite’s awe-inspiring beauty and exotic grandeur. The name Kianga™, taken from the Swahili word for ‘burst of light’, is Jewelry Television™’s exclusive round brilliant cut with 57-58 triangle and kite facets that intensifies the gentle lilac and light blue hues of tanzanite to a new level of distinction.

Kunzite- is a gemstone variety of spodumene. It is known for a range of pink-violet to light-violet colors, but has also been identified in canary yellow, colorless, brown, and greenish-violet. On Mohs' scale of hardness, kunzite ranks 6.5 to 7. It has a vitreous luster, and kunzite sources include Brazil (Minas Gerais), Afghanistan, Burma (Myanmar), Madagascar, Pakistan, and the United States.

Kutamani Tanzanite™ - From the exotic east African country of Tanzania comes a rising new tanzanite star, Kutamani Tanzanite™. Named from the native Swahili language, Kutamani translates to “aspire”. While Kutamani Tanzanite™ has a fewer internal characteristics than our other tanzanite products, its regal, rich hues more than make up for their presence. Kutamani Tanzanite™ gives you the aspirational look of the finest tanzanite at extremely affordable pricing. Aspire to possess one of the most beautiful gemstones on the planet today….Kutamani Tanzanite™, only on Jewelry Television and jtv.com.

Kyanite- has a similar chemical composition to andalusite and fibrolite, but it has a different crystal structure. Kyanite exhibits a small range of colors including blue, colorless, blue-green, and brown. On Mohs' scale of hardness, kyanite ranks 4 to 4.5 and it has a vitreous luster. Primary kyanite sources include Burma (Myanmar), Brazil, Kenya, Austria, Switzerland, Zimbabwe, and the United States.

L

Lab-Grown- Man-made gemstone that has nearly the same physical, optical and chemical properties of a natural gemstone.

Loupe- Any small magnifying glass mounted for hand use, to hold up to the eye socket or attach to a pair of glasses.

Luster -The hue and depth of reflection from pearls, opals or other opaque stones.

M

Make- A trade term referring to the quality of a gemstone's cut.

Matrix- The rock in which gemstone material is found. Some matrix material may remain in a finished gemstone--the veining in turquoise is a common matrix seen in a finished gemstone.

Marquise shape- A double-pointed, boat-shaped stone that is long and thin with gently curved sides coming to a point on either end. Marquise is part of the brilliant-cut family; ideally cut it has 58 facets.

Melee- Gemstones of approximately .18 carats or less. May refer to all gemstones or cutting styles, but is usually used for round, facetted diamonds.

Millegrain- A style of setting in which the stone is held in place by a row of tiny beads along the girdle of the stone.

Mineral- Inorganic substances occurring naturally and having a definite chemical composition and crystal structure.

Mineralogy- The study of minerals, including their physical and chemical properties.

Mixed-cut - This cut has both step-cut and brilliant-cut facets. Mixed cuts combine the beauty of the emerald cut with the sparkle of the brilliant cut.

MOHS Scale- A scale of hardness with numbers from one to ten assigned to ten minerals of increasing hardness from talc to diamonds.

MOHS Rating
MOHS Rating	Gemstone	Mineral Group
10	Diamond
9	Ruby, Sapphire	Corundum
8	Topaz	Topaz
7.5	Emerald	Beryl
7.5	Aquamarine	Beryl
7	Amethyst	Quartz
7	Amethyst	Quartz
6.5	Peridot
5.5 - 6.5	Opal
3	Onyx

Mele- Small, usually round diamonds less than .10 carats in size.

Monoclinic System- A crystal system which consists of three axes, each unequal in length with two intersecting at oblique angles and the third perpendicular to the other two.

Mounting- The portion of a piece of jewelry which holds a gemstone.

N

Natural- A diamond characteristic that is part of the surface of a polished diamond that was not cut or polished during the cutting process.

Normal- In the study of light, an imaginary line perpendicular to a surface. Used in gemology to describe the angle at which light strikes an object.

O

Oiling- This technique is commonly used on emeralds. The purpose of this technique is for the oil to fill the fine cracks that weaken the green color. The oil fills the cracks making them "disappear" and thereby improving the color.

Opalescence- Milky or pearly appearance.

Opaque- The quality of not allowing the transmission of light.

Optic Character- The effect a material has on the transmission on light.

Optical Properties- The behavior of light within a material.

Organic Gem- Naturally occurring substances wholly or partly derived from plants or animals--coral, jet, pearls.

Oriented Stone- A gemstone cut to place the optical axis, and resulting phenomenon, in proper position--star sapphires and star rubies.

Orthorhombic System- A crystal system which consists of three axes, each unequal in length and intersecting at ninety-degree angles.

P

Parting- Flat, smooth breakage of a mineral along planes or twinning, commonly found in corundum.

Paste- Glass usually containing lead oxide and cut to simulate a gemstone.

Pave- A type of setting where a number of small stones are set together. It literally means paved with diamonds.

Pavilion- Bottom portion of the stone, under the girdle, measuring to the culet. It is the area below the girdle consisting of 23 facets in the round-brilliant-cut diamond.

Pear shape- Term used to describe any diamond whose girdle outline resembles a pear shape. Ideally cut pear shapes have 58 facets.

Phenomenon- An optical effect which appears in certain gemstone materials. Often revealed by or enhanced by proper fashioning.

Phosphorescence- A continuing glow exhibited by some gemstones after the source of illumination has been removed.

Pinpoint- An inclusion within a diamond. A gathering of pinpoints is called a "cluster" or "cloud." A cloud or cluster can appear as a hazy area in the diamond, a pinpoint appears as a dot.

Play of Color- Prismatic flashes of color seen within a gemstone. The color display in Opal.

Pleochroism- Change of colors observed in double-refractive gemstones when viewed different directions. Selective absorption and varying transmission rates of light cause the color change when the gemstone is viewed along different optical axes.

Point- Term meaning one-hundredth of a carat -- approximately the size of one-half a grain of sand.

Polish- Indicates the care taken by the cutter in shaping and faceting the rough stone into a finished and polished diamond.

Poor cut - A poorly cut diamond can be either cut too deep or too shallow. A deep or shallow cut diamond will lose or leak light through the side or bottom. This results in less brilliance and value.

Princess cut- A square or sometimes rectangular-shaped modified brilliant-cut diamond.

Prong or claw setting- The metal tip or bead that actually touches the stone and holds it into place. This setting usually consists of four or six claws that cradle the stone. Because this setting allows the maximum amount of light to enter a stone from all angles, it sometimes can make a diamond appear larger and more brilliant than its actual weight. This setting can also hold larger diamonds more securely.

Proportion- The proportions of a diamond are very important, so that the maximum amount of light be reflected off and out of a stone. Proportion is the relationship between the angles of the facets of the crown and pavilion.

Q

Quartz- is one of the most common gem families and can be found all around the world. Quartz comprises several different groups of gems from crystalline quartz (crystals viewable by the naked eye) and cryptocrystalline (microscopic crystals). Crystalline quartz includes amethyst, aventurine, rock crystal, blue quartz, citrine, hawk's eye, prasiolite, quartz cat's-eye, smoky quartz, rose quartz, and tiger's eye. Cryptocrystalline quartz is also known as chalcedony and includes agate, bloodstone, carnelian, chrysoprase, jasper, moss agate, onyx, and sard.

Quartz movement- Many watches are equipped with a quartz movement, which provides very accurate performance at a minimal cost. Quartz crystals, common in many electronic devices, provide a consistent way of measuring time over a wide range of environmental conditions. A battery powers most quartz-movement watches, which can last years due to the crystal's energy efficiency.

R

Radiant cut- A rectangular or square shaped diamond with step-cut and scissor-cut on the crown, and a brilliant-cut on the pavilion.

Reconstructed Stone- A man-made gemstone produced by fusing together small particles of a natural stone.

Reflection- Light returned to the viewer after striking a surface without entering it.

Refraction- The change of velocity and resulting bending of light as it passes from one medium into another medium of different optical character.

Refractive Index- The ratio of speed of light in air to its speed within a substance.

Refractometer- An instrument used to measure the degree of refraction with a gemstone. One of the primary tests to identify gemstone material.

Rondelles- Small, jeweled or facetted beads often used as spacers in a string.

Rough- Uncut diamonds or gemstones.

S

Scarab- A gemstone cut in the form of a beetle.

Schiller- The appearance of a floating, billowy light in cabochon gemstones or a stationary sheen on the flat surface of a stone. Seen in certain Feldspars such as Moonstone.

Scintillation- When light reflects from a diamond, the sparkling flashes that come from the facets of the gem are known as scintillation.

Scrimshaw- Carved or engraved ivory or vegetable ivory. The engraved lines and textured surfaces are often colored with inks and dyes.

Setting- A mounting or the portion of a mounting which actually holds the stone.

Shallow cut- When a diamond is cut too shallow, it will lose or leak light through the side or bottom. This results in less brilliance and value.

Shape- Form or appearance of a diamond; i.e.: whether the diamond is round, triangular, square, marquise, pear, oval or heart-shaped.

Solitaire- A single diamond or stone set by itself in mounting.

Stability- The ability of a gemstone to resist deterioration.

Star Stone- A gemstone in which the phenomenon of asterism is visible.

Step cut- With rows of facets that resemble the steps of a staircase. The emerald cut and the baguette are examples of the step cut.

Strain- Irregularity in the ordered structure of the atoms in a crystal.

Strass- Glass containing a high amount of lead oxide and cut to simulate a gemstone. Named for its inventor Josef Strass.

Substitute- A substance used to imitate a more valuable gemstone. The substitute substance may be natural or man-made.

Synthetic- A man-made gemstone that has nearly the same physical, optical and chemical properties of a natural gemstone. Lab-grown gemstone.

Symmetry- Symmetry is the arrangement of the facets and finished angles created by the diamond cutter. Excellent symmetry of a well-cut and well-proportioned diamond can have a great effect on the diamond's brilliance and fire. Grading reports will often state the diamond's symmetry in terms Excellent, Very good, Good, Fair, or Poor.

T

Table- The top surface of a cut diamond or gemstone.

Table facet -- This is the largest facet of a diamond. It is located on the top of the diamond. The table facet is sometimes referred to as the "face."

Table spread -- Term used to describe the width of the table facet, often expressed as a percentage of the total width of the stone.

Tension setting -- A diamond is held in place by the pressure of the band's metal.

Tetragonal System- A crystal system which consists of three axes, two of equal length and perpendicular to one another, the third perpendicular to the plane of the others.

Tiffany Setting- A solitaire (single-stone) setting for a facetted stone consisting of six long, slender prongs.

Tone- The relative lightness or darkness of a color.

Translucent- A substance that allows transmitted light to clearly pass through. Objects cannot be seen through a translucent substance.

Transparent- A substance that allows transmitted light to clearly pass through. Objects can be seen through a transparent substance.

Trichroism- The transmission of three different colors in three different optical planes as light passes through a gemstone material. May be used to distinguish one gemstone material from others.

Triclinic System- A crystal system which consists of three axes, all of unequal lengths and at oblique angles to each other.

Trillion shape -- Is a triangular-shaped diamond with 50 facets. Trillions are commonly used as side-stones.

Triscotahedron- A twenty-four sided geometric solid. One of the crystal forms of the Isometric crystal system.

Tube Setting- A bezel setting in which a bearing cut into the end of a tube.

Tulip Setting- A prong setting with a small base where it is attached to the body of the jewelry piece and usually has a peg on the base which is inserted into a hole for solder attachment.

Tumbled Stone- A gem with an irregular or baroque shape. Polished by random application of an abrasive material.

U

Uniaxial Stone- A gemstone possessing one optical axis. Crystals of the hexagonal or tetragonal system are uniaxial.

V

Vegetable Ivory- Any hard, white or cream-colored product of a plant which simulates elephant ivory. It has gained in popularity as the harvesting of animal has been banned or severely limited.

Vermei-l is real gold that is chemically bonded onto sterling silver. Vermeil allows you to have the look of gold at a fraction of the price.

Vitreous- describes to a glass-like luster on a stone.

W

Well cut - Well-cut proportions ensure the maximum compromise between fire and brilliance. When light enters a properly cut diamond, it is reflected from facet to facet, and then back up through the top, exhibiting maximum brilliance, fire and sparkle.

Whiplash Curve- Flowing lines that bend and twist as in Art Nouveau designs.

White gold- uses silver-colored alloys like silver, zinc, or nickel to decrease the yellow tint of gold. To intensify its white luster and eliminate the yellow tint, white gold is sometimes plated with rhodium or platinum.

X

Xenolith- Rock fragment or mineral found in igneous rock that is not of igneous origins.

X-ray- Electromagnetic radiation that has a very short wavelength, emitted from a substance when it is attacked by a line of electrons in a vacuum. Machines are able to produce this, and they are known as x-ray machines. They are useful in geology and mineralogy for the study of the chemical constituents of rocks and minerals.

Y

YAG- is yttrium aluminum garnet (Y3Al5O12), a manmade material used as a gemstone. It was developed in the 1960s and has been sold as a gem in the market since 1969. Don't be fooled by the "garnet" in YAG's name; YAG has the same basic crystal structure as garnet, but it is not a garnet. It also doesn't have a counterpart in nature; that is, it's not a synthetic version of any "real" or "natural" gemstone. YAG is most often used as a diamond stimulant, but it can be almost any color. It is a fairly hard 8 on Mohs' hardness scale.

Z

Zircon- is a beautiful, natural gemstone with a high refractive index and strong dispersion. Zircon should not be confused with cubic Zirconia, as the two are completely unrelated. Zircon exhibits a range of colors including yellow, brown, orange, red, violet, blue, green, and colorless. Blue zircon is usually heated, but only brownish zircon from Cambodia heats to that popular blue color. On Mohs' scale of hardness, zircon is 6.5 to 7 and it has a vitreous to brilliant luster. Zircon sources include Burma (Myanmar), Cambodia, Sri Lanka, Thailand, Australia, Brazil, Korea, Madagascar, Mozambique, Nigeria, Tanzania, and Vietnam.

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