how to facet
gemstone main cabochon creation
mineral data
Mineral Name: quartz overview
Gem Names: amethyst - citrine - caringorm - amatrene - rock crystal - rose - agatte - jasper - onyx - carnelian - aventurine - bloodstone - tiger eye -petrified wood - sard - sard onyx - fossil dinosaur bone - fire agate - and this list goes on...
Chemistry: n SiO2
Class: silicates (amorphous - cryptocrystaline - tectosilicates)
Crystal Sys: hexagonal
Hardness: 6.5 - 7 Specific Gravity: 2.65 - 2.91
Fracture: conchodial - splintery Refractive Index: 1.54 - 1.55
Dispersion: 0.013
Misc Prop: There are four basic varieties of quartz as far as the gem trade is concerned. The first is the crystalline form and produces the clear gemstones that are usually cut into faceted stones. There are about 70 new photographs in this section.

The second is the crypocrystalline form and produces the material chalcedony, which is the major constituant of agates and jaspers. I have also included prase, tigereye, and aventurine in this general category. There are more than 130 new images of agates, morethan 100 new shots of jasper, and abouit 20 "others".

The third variety is also a chalcedony, but it is a replacment product that replaces organic (or living) material to produce casts. (fossil wood, dinosaur bone, fossil coral, fossil dinosaur "poop", etc.) 15+ new photos of these materials.

The final variety is amorphous silica (non-crystalline) and can be found in opal, obsidian, tecktites, and other forms of natural glass. These are listed in seveal other areas. Opals have their own area with 20+ new photos.

Color: In gemstones, color, is often the key to naming or describing the particular variety. Hence look for this information below in the various descriptions. Color, opacity, and homogeneity often determine the placement of value on any given stone, and are all optical properties of the particular stone.
Specific Data:
amethyst - citrine - ametrine - smokey quartz - tourmalated quartz - rutilated quartz
fortification - plume - moss - tubular - dendritic - and others
plain - brecciated - orbicular - scenic -
golden - red - blue - green - maramumba
wood - dinosaur bones - fern - coral
brazilian - australian - mexican
obsidian - tektite -