Amethyst - is a purple variety of quartz often used as an ornament. It is also the birthstone associated with February.

Aquamarine - is a gemstone-quality transparent variety of beryl, having a delicate blue or turquoise color, suggestive of the tint of seawater. Aquamarine (along with Bloodstone) is the birthstone associated with March.

Asterism - is an optical phenomenon displayed by some rubies, sapphires, and other gems of an enhanced reflective area in the shape of a "star" on the surface of a cabochon cut from the stone.

Baguette - is a gemstone, often a diamond, cut in a narrow rectangular shape. Small diamonds cut this way are often used as accents.

Bead Setting - is a generic term for setting a stone directly into metal using gravers, which are essentially tiny chisels. A hole is drilled directly into the metal surface, and then a ball burr is used to make a concave depression just the size of the stone.

Bezel - is simply a band of metal which is shaped into the size and shape of the gem and then soldered into place on the metal of the jewelry. The next step is to place the prepared stone into the bezel, or metal band and the metal is pressed down over the edges of diamond which locks it into place.

Blemishes - surface defects on a gem stone such as: polish lines, grain boundaries, naturals, scratches, nicks, pits and chips.

Brilliant Cut - is the most popular cut shape for diamonds. The shape resembles that of a cone and is meant to maximize light return through the top of the diamond.

Burnish Or Flush Setting - is similar to bead setting, but after the stone is inserted into the space, instead of using a graver to lift beads, a rubbing tool us used to push the metal all around onto the stone, not very different from bezel setting.

Cabochon - is a gemstone which has been shaped and polished as opposed to facetted.

Carat- is a unit of mass used for measuring gemstones and pearls, and one caret is exactly 200 milligrams.  The carat is divisible into one hundred points of two milligrams each.

Channel Setting - is a method whereby stones are suspended between two bars or strips of metal, called channels. Often when setting small stones and the bars go in a linear line with the design it is called channel setting, and when the bars cross the lines of the design, it's called bar set.

Citrine- also called citrine quartz, is variety of quartz. It ranges in color from a pale yellow to brown.  Citrine is one of three traditional birthstones for the month of November.

Clarity - is a quality of a stone relating to the existence and visual appearance of internal characteristics of a stone called inclusions, and surface defects called blemishes.

Cleavage - describes the way a mineral may split apart along various planes. In thin sections, cleavage is visible as thin parallel lines across a mineral.

Color - indicates the appearance of the mineral in reflected light or transmitted light for translucent minerals (i.e. what it looks like to the naked eye).

Crown - is the faceted portion of a gem which rises above the girdle.

Culet- is a flat face on the bottom of a gemstone.  It is added largely to protect the integrity of the gemstone.  Culet facets are common on modern brilliant cut diamonds.

Cut - has two meanings in relation to diamonds. The first is the shape: round, oval and so on. The second relates to the specific quality of cut within the shape, and the quality and price will vary greatly based on the cut quality. Since diamonds are very hard to cut, special diamond bladed edges are used to cut them.

Diamond- is an allotrope of carbon. It is the hardest known natural material and the third-hardest known material after aggregated diamond nanorods and ultrahard fullerite. Its hardness and high dispersion of light make it useful for industrial applications and jewelry.  Diamond is the birthstone associated with April.

Dispersion- the ability of the material to split white light into itss component spectral colors. 

Emerald- is any of the various green gemstones, especially a green transparent form of beryl, highly valued as a precious stone.  Emerald is the birthstone associated with May.

Facets- are flat faces on geometric shapes.  Gemstones commonly have facets cut into them in order to improve their appearance.  The most famous facet arrangement is probably the round brilliant cut, used for diamond and many colored gemstones.

Fancy Cut — is a cut other than the round brilliant, which the particular crystal shape lends itself to.

Fire - is a function of dispersion, the flashes of spectral colors only apparent after cutting.

Fracture - describes how a mineral breaks when broken contrary to its natural cleavage planes.

Fracture Filling- is a technique on diamonds to better conceal their flaws.  The glass filling of diamonds often follows the laser drilling and acid-etching of inclusions, though if the fractures are surface-reaching, no drilling may be required.

Garnet- is a group of minerals that have been used since the Bronze Age as gemstones and abrasives. Garnets are most often seen in red, but are available in a wide variety of colors spanning the entire spectrum.  Garnet is known as the birthstone for January.

Gemological Institute of America, or GIA, - is a non-profit institute dedicated to research and education in the field of gemology. The GIA is also well known for its gem identification and grading services, and developed the famous "four Cs" (Cut, Clarity, Color and Carat weight) methodology of grading diamonds.

Girdle- is the division between the crown and the pavilion on a gemstone.  The girdle may be frosted, polished smooth, or faceted.

Hardness - often measured using the MOHS scale, is the resistance a material has to scratching.

Inclusions- are the location of internal flaws.  Inclusions may include clouds, feathers, included crystals or minerals, knots, cavities, cleavage, bearding, or internal graining

Iridescence - is an optical phenomenon characterized as the property of surfaces in which hue changes according to the angle from which the surface is viewed.

Jade - is an ornamental stone. The term jade is applied to two different rocks that are made up of different silicate minerals.

Loupe - is a type of magnification device used to see things one is looking at more closely. In this respect, they are simply a form of a modified microscope, allowing the user to be able to better apply the phenomenon of microscopy to his or her trade.

Luster - indicates the way a mineral's surface interacts with light and can range from dull to glassy (vitreous).

Marquise Cut - is an oval stone which is pointed at both ends or a double-pointed, boat-shaped stone that is long and thin with gently curved sides.

Mixed Cuts - share aspects of both (modified) brilliant and step cuts: they are meant to combine the weight preservation and dimensions of step cuts with the optical effects of brilliants. Typically the crown is brilliant cut and the pavilion step-cut.

Modified Brilliant Cuts - include the marquise or navette, heart, triangular trillion (also trillian or trilliant), oval, princess and the pear or drop cuts.

MOHS Scale - how the physical hardness of a mineral is usually measured. This scale is relative and goes from 1 to 10. Minerals with a given Mohs hardness can scratch the surface of any mineral that has a lower hardness than itself.

Oiling - refers to when emeralds are oiled as part of the post lapidary process, in order to improve their clarity. Cedar oil, having a similar refractive index, is often used in this generally accepted practice.

Onyx - is a cryptocrystalline form of quartz. The colors of its bands range from white to almost every color (save some shades, such as Purple or Blue.) Commonly, specimens of onyx available contain bands of colors of white, tan, and brown.  Pure black Onyx is common, and perhaps the most famous variety, but not as common as Onyx with banded colors.

Opal- is a mineraloid that ranges from clear through white, gray, red, yellow, green, shore, blue, magenta, brown, and black. Of these hues, red and black are the most rare and dear, whereas white and green are the most common.  Opal is the traditional birthstone of the month of October.

Pavilion - is the lower half of the stone below the girdle.

Pearl - is a hard, rounded object produced within the soft tissue (specifically the mantle) of a living shelled mollusk.  Pearl is considered to be the birthstone for June.

Peridot- is the gem quality variety of forsteritic olivine. Peridot is one of the few gemstones that come in only one color. The depth of green depends on how much iron is contained in the crystal structure, and varies from yellow-green to olive to brownish green.  Peridot/olivine is the birthstone of August.

Point - is one-hundredth of a carat.

Prong Setting - is the simplest and most common type of setting, largely because it uses the least amount of metal to hold the stone, thus showing it off to its best advantage. Generally it is simply some number of wires, called prongs, which are of a certain size and shape, arranged in a shape and size to hold the given stone, and fixed at the base.

Refraction - the change in direction (or bending) of light rays as they pass through a gemstone.

Rhinestone - is a diamond simulant made from rock crystal, glass or acrylic.  Originally, rhinestones were rock crystals gathered from the river Rhine.

Rough - term used to describe gemstones that are uncut.

Ruby - is a light pink to blood red gemstone, a variety of the mineral corundum. The common red color is caused mainly by the element chromium.  Other varieties of gem-quality corundum are called sapphires.  Ruby is the birthstone associated with July.

Sapphire - includes any gemstone quality varieties of the mineral corundum except the fully saturated red variety, which is instead known as ruby.  Sapphire is the birthstone associated with September.

Scintillation - is brightly colored flashes of reflected light.

Solitaire Setting - A single gemstone set by itself in mounting.

Step Cuts - are stones whose outlines are either square or rectangular and whose facets are rectilinear and arranged parallel to the girdle are known as step- or trap-cut stones. These stones often have their corners truncated, creating an emerald cut with an octagonal outline.

Table - the top surface of the crown of a gemstone.

Tanzanite - is the blue/purple variety of the mineral zoisite discovered in the Meralani Hills of northern Tanzania in 1967, near the city of Arusha. It is a popular and valuable gemstone when cut, although its durability is somewhat lacking; its tendency to break sometimes precludes appropriate use as a ring stone.

Topaz - is a silicate mineral of aluminium and fluorine.  Pure topaz is transparent but is usually tinted by impurities; typical topaz is wine or straw-yellow. They may be made white, gray, green, blue, pink or reddish-yellow and transparent or translucent.  Yellow topaz is the traditional November birthstone while Blue topaz is thought to be the birthstone for December.