Chemistry Reference
In-Depth Information
TABLE 18
Gemstones
Gemstone
and Varieties
Composition
Color
Metal Silicates
Adularia
Potassium aluminum silicate
Varies
Beryl
Beryllium aluminum silicate
aquamarine
Green-blue
emerald
Brilliant green
Jade
jadeite
Sodium aluminum silicate
Mainly green, but also
nephrite
Calcium magnesium silicate
other colors
Quartz
Silica
agate
Banded or patterned
amethyst
Purple
jasper
Varies
onyx
Black and white bands
rock crystal
Transparent
Topaz
Aluminum fluorosilicate
Pink to red
Tourmaline
Complex borosilicate
Variable
Turquoise
Hydrous copper aluminum silicate
Light blue
Zircon
Zirconium silicate
Variable
Metal Oxides
Chrysoberyl
Berylium aluminum oxide
cat's eye
Variable
alexandrite
Red/green
Corundum
Aluminum oxide
ruby
Red
sapphire
Any color but red
Spinel
Magnesium aluminum oxide
Variable
Unrelated Composition
Diamond
Carbon
Usually colorless
Garnet
Mixture of several minerals
Variable
Opal
Variable
Flashing
Organic Origin
Amber
Fossil resin
Yellow//brown/red
Coral
Calcium carbonate
Red/pink
Ivory
Mixture of calcium carbonate
Creamy white
Jet
Fossilized wood
Black
Nacre
Aragonite + organic compounds
Mainly white; iridescent
Pearl
Aragonite + organic compounds
Mainly white; iridescent
