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MATERIAL HARDNESS*

SPECIFIC*
GRAVITY

REFRACTIVE INDEX* ENHANCEMENT** SPECIAL CARE**
Normal Range Bire. Most Commonly Used Method Code
alexandrite
Alexandrite
 8½
3.73+.02
 1.746-1.755 + .004 - .006 .008 - .010 None A Normal
amethyst
Amethyst
 7
2.66+.03
-.02
 1.544- 1.553 +.000 .009 None A Normal
andalusite
Andalusite
 7 - 7½
3.17+.04
 1.634- 1.643 +.005 .007- .013 None A Normal
aqua
Aquamarine
 7½ - 8
2.72+.18
-.05
 1.577- 1.583 +.017 .005- .009 Heated H Normal
ametrine
Ametrine
 7
2.66+.03
-.02
 1.544- 1.553 +.000 .009 None A Normal
beryl
Beryl
 7½ - 8
2.72+.18
-.05
 1.577- 1.583 +.017 .005- .009 None A Normal
chrysoberyl
Chrysoberyl
 8½
3.73+.02
 1.746- 1.755 + .004 - .006 .008- .010 None A Normal
citrine
Citrine
 7
2.66
 1.544- 1.553 +.000 .009 Heated H Normal
diamondDiamond
 10
3.52
 2.417 - - None A Normal
emerald
Emerald
 7½ - 8
2.72
 1.577- 1.583 +.017 .005- .009 Oiled O Avoid temp. changes, steaming, chemicals and ultrasonic.
garnet
Garnet
 7 - 7½
3.78
 1.746 + .010 - .026 - None A Avoid sudden temperature changes.
iolite
Iolite
 7 - 7½
2.61
 1.542- 1.551 + .045 - .011 .008- .012 None A Normal
kunzite
Kunzite
 6½ - 7
3.18
 1.660- 1.676 +.005 .014- .016 Irradiated R Avoid strong light and ultrasonic - color may fade.
opal
Opal
 5 - 6½
2.15
 1.450 + .020 - .080 - None A Avoid heat, chemicals and ultrasonic.
peridot
Peridot
 6½ - 7
3.34
 1.654- 1.690 +.020 .035- .038 None A Avoid sudden temperature changes and chemicals.
rhodolite
Rhodolite
 7 - 7½
3.84
 1.760 + .010 - .020 - None A Avoid sudden temperature changes.
rubellite
Rubellite
 7 - 7½
3.06
 1.624- 1.644 + .011 - .009 .018- .040 Irradiated R Normal
ruby
Ruby
 9
4.00
 1.762- 1.770 + .009 - .005 .008- .010 Heated H Normal
sapphire
Sapphire
 9
4.00
 1.762- 1.770 + .009 - .005 .008- .010 Heated H Normal
spinel
Spinel
 8
3.60
 1.718 + .017 - .008 - None A Normal
tanzanite
Tanzanite
 6 - 7
3.35
 1.691- 1.700 +.005 .008- .013 Heated H Avoid sudden temperature changes and ultrasonic.
diopside
Tsavorite
 7 - 7½
3.61
 1.740 + .020 -. 010 - None A Avoid sudden temperature changes.

topaz
Topaz

 8
3.53
 1.619- 1.627 -+.010 .008- .010 Irradiated & Heated R Normal
tourmaline
Tourmaline
 7 - 7½
3.06
 1.624- 1.644 +. 011 -. 009 .018- .040 Heated H Normal
zircon
Zircon
 6 - 7½
4.70
 1.925- 1.984 + .040 - .145 .000- .059 Heated H Avoid Abrasives