| |
Physical
properties of Gems:
|
Name
|
Hardness
|
Chemistry
|
Density
|
Crystal
|
|
Actinolite
|
5.5
|
Amphibole Group
|
3.05
|
Monoclinic
|
|
Agate
|
6.5 - 7
|
SiO2
|
2.57 - 2.64
|
Hexagonal
|
|
Alexandrite
|
8.50
|
BeAl2O4
|
3.73
|
Orthorhombic
|
|
Amethyst
|
7
|
SiO2
|
2.66
|
Hexagonal
|
|
Ametrine
|
7
|
SiO2
|
2.66
|
Hexagonal
|
|
Andalusite
|
7 - 7.5
|
Al2SiO5
|
3.13 - 3.21
|
Orthorhombic
|
|
Apatite
|
5
|
Phosphate group
|
3.17-3.23
|
Hexagonal
|
|
Aquamarine
|
7.5
|
Be3Al2(SiO3)6
|
2.67-2.745
|
Hexagonal
|
|
Axinite
|
6.5 - 7
|
|
3.29
|
Triclinic
|
|
Benitoite
|
6.5
|
BaTiSi3O6
|
3.65 – 3.68
|
Hexagonal
|
|
Beryl
|
7.5
|
Be3Al2(SiO3)6
|
2.67-2.745
|
Hexagonal
|
|
Bi
Color Tourmaline
|
7-7.5
|
(NaCa)(LI,MgFe,Al)9B3Si6(O,OH)31
|
3.06 (.05, +.15)
|
Hexagonal
|
|
Bixbite
|
7.5
|
Be3Al2(SiO3)6
|
2.67-2.745
|
Hexagonal
|
|
Brazilianite
|
5.5
|
A hydrous sodium aluminum phosph
|
2.940 - 2.998
|
Monoclinic
|
|
Calcite
|
3
|
CaCO3
|
2.70
|
Triclinic
|
|
Chalcedony
|
6.5
|
SiO2
|
2.57 – 2.64
|
Hexagonal
|
|
Chrome
Tourmaline
|
7-7.5
|
(NaCa)(LI,MgFe,Al)9B3Si6(O,OH)31
|
3.06 (.05, +.15)
|
Hexagonal
|
|
Chrysoberyl
|
8.50
|
BeAl2O4
|
3.73
|
Orthorhombic
|
|
Chrysoberyl
Cats Eye
|
8.5
|
BeAl2O4
|
3.73
|
Orthorhombic
|
|
Chrysocolla
Quartz
|
7
|
SiO2
|
2.66
|
Hexagonal
|
|
Chrysoprase
|
7
|
SIO2
|
2.65 - 2.66
|
Hexagonal
|
|
Citrine
|
7
|
SiO2
|
|
Trigonal
|
|
Clinohumite
|
6 - 6.5
|
Magnesium Silicate Fluoride OH
|
3.17 - 3.35
|
Monoclinic
|
|
Color
Change Garnet
|
7-7.5
|
Nesosilicate
|
3.80
|
Cubic
|
|
Color
Change Sapphire
|
9
|
AL22O3
|
4.00
|
Hexagonal
|
|
Danburite
|
7
|
calcium borosilicate
|
3.00
|
Orthorhombic
|
|
Demantoid
|
6.5
|
Ca3Fe2(SiO4)3
|
3.82 - 3.50
|
Cubic
|
|
Diamond
|
10
|
C
|
3.52
|
Cubic
|
|
Dinosaur
Bone
|
7
|
SIO2
|
2.66
|
Hexagonal
|
|
Diopside
|
6
|
CaMgSi2O6
|
3.25 - 3.55
|
Monoclinic
|
|
Dioptase
|
5
|
CuSiO2(OH) 2</SU< SPAN>
|
3.28 – 3.55
|
Hexagonal
|
|
Emerald
|
7.5-8
|
Be3Al2(SiO3)6
|
2.72 (-.05, +.12)
|
Hexagonal
|
|
Enstatite
|
5.5
|
MgSiO3
|
3.26-3.28
|
Orthorhombic
|
|
Epidote
|
6.5
|
Calcium aluminum silicate
|
3.4
|
Monoclinic
|
|
Fibrolite
|
6 - 7.5
|
Al2SiO5
|
3.14 - 3.25
|
Orthorhombic
|
|
Fire
Agate
|
7
|
SiO2
|
2.65
|
Trigonal
|
|
Fluorite
|
4
|
CaF2
|
3.18
|
Cubic
|
|
Fresh
Water Pearls
|
3.5 - 4.0
|
CaCO3
|
2.66 – 2.78+
|
Not applicable
|
|
Grossularite
|
7.25
|
Ca3Al2(SiO4)3
|
3.65
|
Cubic
|
|
Hemimorphite
|
5
|
(Zn4Si2O7(OH)2.H2O)
|
3.44
|
Orthorhombic
|
|
Hessonite
|
7.25
|
Ca3Al2(SIO4)3
|
3.65
|
Cubic
|
|
Idocrase
|
6.5
|
nesosilicate or sorosilicate
|
3.3 - 3.5
|
Tetragonal
|
|
Indicolite
|
7-7.5
|
(NaCa)(LI,MgFe,Al)9B3Si6(O,OH)31
|
3.06 (.05, +.15)
|
Hexagonal
|
|
Intarsia
|
varies
|
|
|
Not applicable
|
|
Kornerupine
|
6.50
|
|
3.25 - 3.35
|
Orthorhombic
|
|
Kunzite
|
7
|
LiAlSi2O6
|
3.17 - 3.19
|
Monoclinic
|
|
Kyanite
|
4.5 – 7.0
|
AL2SIO5
|
3.56 – 3.68
|
Triclinic
|
|
Labradorite
|
6 - 6.5
|
KAlSi3O8
|
2.69
|
Triclinic
|
|
Lapis
|
5.5
|
A complex aggregate
|
2.7-2.9
|
Not applicable
|
|
Malaia
Garnet
|
7 - 7.5
|
[Mg3 + Mn3]AL2(SIO4)
|
3.65 - 4.20
|
Cubic
|
|
Mali
Garnet
|
7.25
|
Ca3Al2(SiO4)3
|
3.65
|
Cubic
|
|
Mawsitsit
|
varies, up to 7
|
|
2.5-3.2
|
Not applicable
|
|
Moonstone
|
6 – 6.50
|
KalSI3O8
|
2.55 – 2.57
|
Monoclinic
|
|
Morganite
|
7.5-8
|
Be3Al2(SiO3)6
|
2.72 (-.05, +.12)
|
Hexagonal
|
|
Opal
|
5.5 - 6.0
|
SIO2nH2O
|
2.65 - 3.00
|
Amorphous
|
|
Peridot
|
6.5
|
(Mg,Fe)2(SiO)4
|
3.34
|
Orthorhombic
|
|
Pezzottaite
|
|
|
3.10
|
Trigonal
|
|
Phenakite
|
7.5-8.0
|
Be2SiO4
|
2.94--2.96
|
Hexagonal
|
|
Prehnite
|
6
|
(CA2Al2SI3O10(OH)2)
|
2.80 - 2.95
|
Orthorhombic
|
|
Quartz
|
7
|
SiO2
|
2.65
|
Trigonal
|
|
Rainbow
Suite
|
|
|
|
Not applicable
|
|
Rhodochrosite
|
4
|
MnCO3
|
3.45 – 3.70
|
Trigonal
|
|
Rhodolite
|
7.25
|
Al2(SiO4)3
|
3.74 - 3.94
|
Cubic
|
|
Rubelite
|
7-7.5
|
(NaCa)(LI,MgFe,Al)9B3Si6(O,OH)31
|
3.06 (.05, +.15)
|
Hexagonal
|
|
Ruby
|
9
|
AL2O3
|
4.00
|
Hexagonal
|
|
Sapphire
|
9
|
AL22O3
|
4.00
|
Hexagonal
|
|
Sapphirine
|
7.5
|
|
3.4-3.5
|
Monoclinic
|
|
Scapolite
|
6
|
Na4Al3Si9O24Cl /CA4Al6Si6O24CO3
|
2.6-2.71
|
Tetragonal
|
|
Scheelite
|
4.5 - 5.0
|
CaWO4
|
5.9 - 6.1
|
Tetragonal
|
|
Sodalite
|
5.5 - 6.0
|
|
2.15 - 2.35
|
Cubic
|
|
Spessartite
|
7.25
|
Mn3Al2(SiO4)3
|
4.14-4.20
|
Cubic
|
|
Sphalerite
|
3.5-4
|
ZnS
|
4.05
|
Cubic
|
|
Sphene
|
5.5
|
CaTiSiO5
|
3.52-3.54
|
Monoclinic
|
|
Spinel
|
8
|
MgAl2O4
|
3.60 (-.03, +.30)
|
Cubic
|
|
Star
Sapphire
|
9
|
AL2O3
|
4.00
|
Hexagonal
|
|
Sunstone
|
6
|
NaAlSi3O8
|
SG 2.62 – 2.65
|
Triclinic
|
|
Taaffeite
|
8 - 8.5
|
Beryllium magnesium aluminate wi
|
3.60 - 3.71
|
Hexagonal
|
|
Tanzanite
|
6-7
|
Ca2(Al,OH)Al2(SIO4)
|
3.30 (+.10, -.10)
|
Orthorhombic
|
|
Topaz
|
8
|
AL(F,OH)2SIO4
|
3.52 - 3.56
|
Orthorhombic
|
|
Tourmaline
|
7-7.5
|
(NaCa)(LI,MgFe,Al)9B3Si6(O,OH)31
|
3.06 (.05, +.15)
|
Hexagonal
|
|
Tsavorite
|
7
|
Ca3Al2(SiO4)3
|
3.61(-.27, +.12)
|
Cubic
|
|
Turquoise
|
5.5-6
|
CuAl6(PO4)4(OH)85H2O
|
2.60- 2.90
|
Triclinic
|
|
Zircon
|
7.50
|
ZrSiO4
|
4.00-4.73
|
Tetragonal
|
|
