Mineral Gemstones
There are 16 mineral gemstones groups:

Beryl
Hardness: 7.5-8
Beryllium aluminum silicate
Specific gravity: 2.63-2.91

Emerald: Intense green or bluish green
Aquamarine: Greenish blue or light blue
Morganite: Pink, purple-pink, or peach
Heliodore: Golden yellow or golden green
Red beryl: Raspberry red
Goshenite: Colorless, greenish yellow, yellow green, brownish

Chrysoberyl
Hardness: 8.5
Beryllium aluminum oxide
Specific gravity: 3.68-3.78

Chrysoberyl: Transparent yellowish green to greenish yellow and pale brown
Alexandrite: Red in incandescent light and green in daylight
Cat's eye: Usually yellowish or greenish

Corundum
Hardness: 9
Aluminum oxide
Specific gravity: 3.96-4.05

Ruby: Intense red
Sapphire: Blue

Diamond
Hardness: 10
Carbon
Specific gravity: 3.51

Colorless to faint yellowish tinge, also variable

Feldspar
Hardness: 6-6.5
Two distinctly different alkali alumino silicates: the Plagioclase and the Alkali Feldspar Series
Specific gravity: 2.55-2.76

Plagioclase Series-
Labradorite: Colorful, iridescent, also transparent
Sunstone: Gold spangles from inclusions of hematite
Peristerite: Blue white iridescence

Alkali Feldspar Group-
Orthoclase: Pale yellow, flesh red
Amazonite: Yellow green to greenish blue
Moonstone: Colorless; also white to yellowish, and reddish to bluish gray

Garnet
Hardness: 6.5-7.5
A group of silicate minerals
Specific gravity: 3.5-4.3

Almandine: Orangy red to purplish red
Almandine-spressartine: Reddish orange
Andradite: Yellowish green to orangy yellow
Demantoid: Green to yellow green andradite
Topazolite: Yellow to orangy yellow
Grossular: Colorless; also orange, pink, yellow, and brown
Tsavorite: Green to yellowish green
Hessonite: Yellow orange to red
Pyrope: Colorless; also pink and red
Chrome pyrope: Orange red
Pyrope-Almadine: Reddish orange to red purple
Pyrope-Apessartine: Greenish yellow to purple
Malaia: Yellowish to reddish orange to brown
Color-change garnet: Blue green in daylight to purple red in incandescent light
Rhodolite: Purplish red to red purple
Spessartine: Yellowish orange
Uvarovite: Emerald green

Jade
Hardness: 6

Nephrite-
Calcium magnesium silicate
Specific gravity: 2.9-3.1
White, deep green, creamy brown

Jadeite-
Sodium aluminum silicate
Specific gravity: 3.1-3.5
White, leafy and blue green, emerald green, lavender, dark blue green and greenish black, deep emerald green

Lapis Lazuli
Hardness: 5-5.5
A rock composed mainly of the mineral lazurite with variable amounts of pyrite and white calcite
Specific gravity: 2.7-2.9

Deep blue, azure blue, greenish blue (bluish color with flecks of white and gold)

Opal
Hardness: 5.5-6.5
Hydrated silica
Specific gravity: 1.98-2.25

White opal: Opaque, porcelain-like white material; colors resemble flashes or speckles
Black opal: Flashes and speckles appear against black background
Water opal: A transparent, colorless opal is the background for brilliant flashes of color
Fire opal: Reddish or orange opal

Peridot (Olivine)
Hardness: 7
Magnesium iron silicate
Specific gravity: 3.22-3.45

Olive to lime green

Quartz
Hardness: 7
Silicon dioxide or silica
Specific gravity: 2.65

Coarsely crystalline varieties of silica-
Rock crystal: colorless
Amethyst: Purple
Citrine: Yellow to amber
Morion: Black
Smoky quartz or cairngorm: smoky gray to brown
Rose quartz: Translucent pink
Green quartz or praziolite: Green

Cryptocrystalline varieties of silica-
Chalcedony and Jasper
Agate: Bull's eye agate, Iris or fire agate, onyx, sardonyx
Bloodstone or heliotrope
Carnelian
Chrysoprase
Moss agate
Plasma
Prase
Sard
Jasper

Spinel
Hardness: 8
Magnesium aluminum oxide
Specific gravity: 3.58-4.06

Balas ruby: Red
Almandine spinel: Purple red
Rubicelle: Orange
Sapphire spinel and ghanospinel: Blue
Chlorspinel: Green

Topaz
Hardness: 8
Aluminum silicate fluoride hydroxide
Specific gravity: 3.5-3.6

Wine yellow, pale blue, green, violet, or red

Tourmaline
Hardness: 7-7.5
Complex aluminum borosilicate
(Elbaite, Dravite, Uvite)
Specific gravity: 3.03-3.25

Achorite: Colorless
Brazilian emerald: Green
Dravite: Brown
Indicolite: Dark blue
Rubellite: pink to red
Siberite: Violet
Verdilite: Green

Turquoise
Hardness: 5-6
Hydrous copper aluminum phosphate
Specific gravity: 2.6-2.8

Sky blue; greenish blue

Zircon
Hardness: 7.5
Zirconium silicate
Specific gravity: 4.6-4.7

Jargon: Variable
Matura diamond: Colorless
Hyacinth: Yellow, orange, red, brown

All info obtained from:
The U.S. Geological Survey

| home | organic gemstones | mineral gemstones | photo gallery |