 |
|
|
Guides and Charts
D |
Danburite
Danburite is a lesser known gemstone originally discovered in Danbury, Connecticut. It is found in colors of wine-yellow, brown and even pink. On Mohs’ scale of hardness, danburite is 7-7.5. It has a vitreous or greasy luster and sources include Burma (Myanmar), Japan, Madagascar, Mexico, Russia and Connecticut.
Dangle Earrings
Also known as drop earrings, this style hangs below the earlobe.
Deco Style
Abstract designs and linear, geometric patterns influenced by the famous Art Deco movement.
Demantoid
Demantoid is a highly valued andradite garnet. It exhibits a range of greens from dull to bright emerald green and on rare occasions displays yellow. On Mohs’ scale of hardness, demantoid is relatively soft at 6.5. It has an adamantine luster and sources include China, Korea, Russia, the United States, and Zaire.
Demi-Hoop Style
Also known as half-hoop design, this earring looks like its name forming only half a circle.
Depth
Depth is the measure of a diamond determined by measure of culet to table.
Depth Percentage
The fire and brilliance of a diamond is based on the depth percentage and table percentage, which equals diamond height divided by diamond width. For a lovely round cut stone, the depth percentage should normally range between 58 and 64 percent.
Diamond
Diamond is crystallized carbon, the only gem composed of a single element. The most popular diamonds are traditionally colorless, but they can also be found in yellow and brown colors. Although much rarer, diamonds known as “fancies” also come in blue, red, pink, green, orange and black. On Mohs’ scale of hardness, diamond is the world’s hardest substance at 10. It has a very strong luster and primary sources include South Africa, Namibia, Australia, Botswana, Russia, Zaire, Brazil, Ghana, Angola and Central African Republic.
Diamond Accent
Diamond accents are small diamonds used in jewelry settings with a combined carat weight of less than one fourth of a carat.
Diamond Cut
Also known as “Brilliant cut,” the style of cutting a stone with multiple facets to maximize brilliance. Modern round brilliant cuts have 58 facets. Diamond cut can also refer to the flat diamond shape in other objects such as necklaces.
Diamond-Cut Rope
This is a chain made of flat diamond-shaped links.
Dichroism
In a doubly refractive crystal, a light beam reflects two different rays. The eye cannot normally see both rays at the same time, but by moving the stone, the eye will observe both rays. The result? The stone exhibits one of two or more different colors (or two or more different color depths) from each angle. This effect is known as dichroism (two-color) or the more common pleochroism (many colors). (Tourmaline is a perfect example.)
Diffusion Treatment
This newcomer to gemstone treatments alters the color of stones through a combination of chemical exposure and long-term heat treatment. The stones begin as colorless or extremely pale and are transformed into vibrant colors. Primarily a surface treatment, wearers should be cautious not to chip stones because the inside of the stone remains colorless. The main distinction between surface diffusion and deep diffusion is the level of penetration, but both are still essentially surface treatments.
Dinner Ring
See Cocktail ring.
Diopside
Diopside is from the pyrozene mineral group. Known for its pure green color, it also can be found in chrome, violet-blue, black, yellow, brown and colorless. It has perfect cleavage and on Mohs’ scale of hardness, diopside is 5-6. Sources include Burma (Myanmar), Finland, India, Madagascar, Austria, Sri Lanka, South Africa and the United States.
Disc Earrings
A disc earring is a round flat earring attached to an earlobe.
Dispersion
Also known as “fire,” dispersion refers to the separation of white light into spectral colors in diamonds and finished gemstones.
Dome
This convex shape is thickest in the center and tapers at the edges.
Door Knocker Earring
This hinged bottom earrings hangs below the earlobe.
Drop Earring
Also known as dangle earrings, this style hangs below the earlobe.
Doublet
Assembled opals combine natural opal with other materials. A doublet contains a slice of opal glued to common opal, glass or other material. A triplet contains a slice of opal glued between a base and a crystal or a glass top. Triplets are usually less expensive than doublets, and both are less expensive than natural opals.
Druse
Druse is an unusually beautiful crust of small crystals on the surface of a rock or mineral. |
|
E |
Earring Back
An earring back is a disk or bead that attaches to an earring post to secure the earring in place.
Earring Jacket
This earring piece is designed with a hole, allowing a stud earring to hold it in place.
Electroplating
This process utilizes a chemical solution and an electric current to cover a base metal with a thin film of gold.
Emerald
Emerald is the most precious member of the Beryl family. It exhibits an incomparable pure green hue but can also be found in a yellowish-green hue. On Mohs’ scale of hardness, emerald is 7.5-8. It has a vitreous luster and sources include Columbia, Zimbabwe, South Africa, Russia (Urals), Afghanistan, Australia (New South Wales, Western Australia), Ghana, India, Madagascar, Malawi, Mozambique, Namibia, Nigeria, Pakistan, Zambia, Tanzania and the United States (North Carolina).
Enamel
Exhibiting a glassy decorative surface, enamel is powdered colored glass that has been fused to metal, pottery or glass.
Engrave
A pattern or design cut or carved into a jewelry piece using an engraving tool.
Epoxy
A resin used in strong adhesives and enamels.
Etched
A decoration or design lightly scratched onto the surface of a jewelry piece.
Eternity Ring
An eternity ring is a ring with gemstones encircling the band.
Eye Clean
Eye clean refers to a stone that appears to have no visible inclusions or imperfections to the naked eye. |
|
F |
Facet
A facet is the flat, polished surface applied to the exterior of a gemstone. The shapes, sizes, numbers, angles, and placement of facets are the key to unlocking the beauty of any gemstone.
Faceted
A gemstone with multiple facets captures the light and enhances the reflected light.
Fancy Cut
Gem cut in any shape other than the standard round cut.
Feldspar
Feldspar refers to a group of minerals that play an important role in the formation of rocks: popular varieties include moonstone and sunstone.
Figaro Chain
A chain with alternating long and round links that is similar in style to the curb link chain.
Figure Eight Safety Catch
This safety catch is a hinged wire in the shape of a figure eight.
Filigree
Fine wire shaped into intricate, intertwined patterns used in jewelry as an open design or soldered to a metal base.
Finish
Finish refers to the surface of a gemstone or piece of jewelry. On stones, it indicates a polished, well cut stone; on jewelry it can describe the texture as well as polish including high polish, matte or brushed.
Fire
Also known as "dispersion," fire refers to the flashes of color appearing in many gemstones as white light is separated into spectral colors (red, orange, yellow, green, blue and violet).
Fire Opal/Cherry Opal
Fire Opal is a unique member of the opal family that displays little or no play-of-color. It is transparent to translucent and displays an orange-red to red to yellow body color. On Mohs’ scale of hardness it is 5.5 – 6. Sources include Australia, Brazil, Guatemala, Honduras, Indonesia, Japan, Mexico, Russia, Nevada, and Idaho. (See Opal.)
Fissure
A fissure is a surface crack on a gemstone.
Fleur-de-lys
This royal insignia of France is an iris with three petals, and is often used as a decoration in jewelry.
Florentine Finish
This surface finish pattern includes a series of engraved parallel lines crossed lightly by perpendicular lines.
Fluoresence
Fluorescence, a fascinating natural phenomenon, is the tendency of some gemstones to reflect a distinct color when exposed to ultraviolet light.
Fluorite
Perfect for collectors and museums, fluorite (fluorspar) is a beautiful but soft stone (Mohs’ scale rating of 4) that comes in a wide range of colors.
Fluted
This design motif features rounded grooves in the surface of the piece.
Fold-Over Clasp
A type of hinged clasp used on necklaces and bracelets.
Fool's Gold
See pyrite.
Fossilized
Organic remains from an ancient geologic period, such as a insects, skeletons or even plants that become preserved over time and hardened into a stone-like substance.
Four Cs
The Four Cs are key indicators of diamond grading and quality. They include “Cut,” “Color,” “Clarity” and “Carat weight.”
Foxtail Chain
An intricate chain including three rows of links braded together.
Fracture Filling
This refers to a stone enhancement method filling in tiny fractures. Fillers include glass, plastic, polymer, resins and oils. For example, emeralds commonly have wax and resins incorporated into fissures to improve appearance.
Fracture
A fracture is a crack against the flat planes or irregular surfaces of a gemstone. A fracture can be characterized as conchoidal (shell-like), uneven, smooth, fibrous, splintery or grainy.
French Clip
Perfect for non-pierced ears, this earring attachment uses a spring clip with padding to hold the earring in place against the back of ear.
French Wire
Primarily used for dangling earrings this curved wire passes through the pierced ear and closes with a catch.
Freshwater Pearl
A pearl produced by a mollusk found in fresh water lakes and rivers.
Full Cut
See Brilliant cut. |
|
G |
Gallery
Gallery describes stamped or patterned wire or strips with a repeated design that is sometimes inspired by antiquity. There are two types of gallery: open (upstanding parts on one side that can shape around a stone) and closed (used in borders).
Garnet
Garnet is a group of colored minerals with a common crystal structure and similar (but not exact) chemical composition. The main garnet groups include pyrope, almandite, spessartite, grossularite, andradite and uvarovite. On Mohs’ scale of hardness, garnet is 6.5-7.5. This wide-ranging family of gemstones covers virtually color and is found all around the world.
Gem
Most gemstones are actually mineral crystals (except for non-mineral gems like pearls, coral and amber). Mineral crystals form through a naturally occurring combination of chemicals, heat and/or pressure. These chemicals affect the shapes and colors of the crystals. Most mineral crystals are tiny, but a few can be cut into gemstones of rare beauty. The three chief characteristics that qualify a mineral crystal as a gemstone and help determine its value are durability, beauty and rarity.
Girdle
A faceted stone can be divided into an upper and lower section. The upper section or top is referred to as a crown. The lower section is referred to as a pavilion. The perimeter where both parts meet is referred to as a girdle. The flat plane on top of the stone is called a table, and the bottom point (when present) is referred to as a culet.
Gold
Treasured for its warm sensuous glow, gold is the most beloved of all metals. Its versatility and ductile nature has made gold the perfect medium for countless artisans and craftsman throughout the ages. For thousands of years, gold has been shaped into jewelry, ornaments, into religious icons and talismans and currency. Gold in its purest state is referred to as 24 karat gold. This is normally too soft for use in jewelry wear, so jewelers will mix gold with an alloy to harden it. (See 10 karat, 12 karat, 14 karat, 18 karat and 24 karat.)
Golden Beryl
Golden Beryl is from the Beryl family of gemstones. It exhibits a range of yellow from lemon-yellow to golden-yellow. On Mohs’ scale of hardness, golden beryl is 7.5-8. It has a vitreous luster and primary sources include Brazil, Madagascar, Namibia, Nigeria, Zimbabwe and Sri Lanka.
Gold Filled
Gold filled refers to the mechanical process of applying two thin gold sheets to core metal such as nickel. To qualify as “gold filled” the amount of gold must be at least 1/20 of the total weight.
Gold Plated
Gold plated refers to an item with a layer at least 10 karat gold bonded to a base metal.
Gold Tone
Jewelry finished with a gold color.
Golden Beryl
The colors of yellow beryl range from pale lemon to rich gold. Beryl with lush golden hues is sometimes referred to as heliodor.
Golden Finish
Jewelry with no actual gold content but finished with a gold look.
Gram Weight
The metal weight of a jewelry piece measured in grams.
Goshenite
Goshenite stones are colorless gemstones from the Beryl family. On Mohs’ scale of hardness, goshenite is 7.5-8. It has a vitreous luster and primary sources include Massachusetts (Goshen), Brazil, China, Canada, Mexico, Russia and the United States.
Greek Key
This design dating back to ancient Greece, features repetitive, interlocking rectangles. (See image).
Green Gold
Green gold is not a naturally occuring phenomena. The green “color” is produced by mixing 24 karat gold with a blend of silver, copper and zinc.
Grooved
A long row or channel cut formed in a line on a jewelry piece.
Grossular
Grossular gemstones are a species within the Garnet family. This species includes several significant gem varieties such as hessonite, tsavorite, leuco garnet, and hydrogrossular. On Mohs’ scale of hardness, it is 3.57 – 3.73. For color and sources, see individual gemstones.
Guard Chain
Fastening to a clasp on a bracelet or wristwatch band, the guard chain keeps charms or ornaments safe from falling in case the clasp accidentally comes undone. |
|
|
|
