Crystal and stones » Detect imitation from natural gemstones

Black gemstones

precious stones — Wed, 16 Sep 2009 15:24:23 +0000

Black gemstones

Hardness. Specific Gravity.

Diamond 10 3.502-3.564 Garnet 6-1/2-7-1/2 3.400-4.500 Jet 3-1/2 1.348 Onyx (a variety of Chalcedony) 6-1/2 2.598-2.610 Quartz 7 2.670 Tourmaline (not unlike Black Resin in appearance) 7-1/4 3.024-3.300

Violet gemstones

precious stones — Wed, 16 Sep 2009 15:22:28 +0000

Violet gemstones

Hardness. Specific Gravity.

Amethyst 7 2.661 Diamond 10 3.502-3.564 Quartz (Amethyst) 7 2.670 Sapphire 9 4.049-4.060 Spinel 8 3.614-3.654 Tourmaline 7-1/4 3.160

Green gemstones

precious stones — Wed, 16 Sep 2009 15:20:47 +0000

Green gemstones

Hardness. Specific Gravity.

Aquamarine 7-3/4 2.701-2.800 Chrysoberyl 8-1/2 3.689-3.752 Chrysolite 6-7 3.316-3.528 Chrysoprase (Quartz) 7 2.670 Diamond 10 3.502-3.564 Dioptase 5 3.289 Emerald and Oriental Emerald 7-3/4 2.690 Euclase 7-1/2 3.090 Garnet (see also Red Garnet) 6-1/2-7-1/2 3.400-4.500 Heliotrope (Chalcedony) 6-1/2 2.598-2.610 Hiddenite (a variety of Spodumene) 6-1/2-7 3.130-3.200 Jade 7 [...]

Blue gemstones

precious stones — Wed, 16 Sep 2009 15:16:45 +0000

Blue gemstones

Hardness. Specific Gravity.

Beryl 7-3/4 2.709-2.810 Diamond 10 3.502-3.564 Dichorite (Water Sapphire) 7-7-1/2 4.049-4.060 Disthene (Kyanite) 5-7 3.609-3.688 Iolite (Cordierite) 7-1/4 2.641 Lapis lazuli 5-1/2 2.461 Sapphire 9 4.049-4.060 Topaz 8 3.500-3.520 Tourmaline 7-1/4 3.160 Turquoise 6 2.800

Pink gemstones

precious stones — Wed, 16 Sep 2009 15:13:50 +0000

Pink gemstones

Hardness. Specific Gravity.

Beryl 7-3/4 2.709-2.810 Diamond 10 3.502-3.564 Ruby 9 4.073-4.080 Spinel 8 3.614-3.654 Topaz (“burnt” or “pinked”), 8 3.500-3.520 Tourmaline 7-1/4 3.024

Red and rose gemstones

precious stones — Wed, 16 Sep 2009 15:11:03 +0000

Red and rose gemstones

Hardness. Specific Gravity.

Carnelian (a variety of Chalcedony) 6-1/2 2.598-2.610 Diamond 10 3.502-3.564 Deep Red Garnet 7-1/4 3.40-4.50 Jasper 7 2.668 Opal (the “Fire Opal”) 5-1/2-6-1/2 2.21 Ruby 9 4.073-4.080 Rhodonite 5-1/2-6-1/2 3.413-3.617 Sapphire 9 4.049-4.060 Spinel Ruby 8 3.614-3.654 Topaz 8 3.500-3.520 Tourmaline 7-1/4 3.024 Zircon 7-1/2 4.70-4.88

Brown and Flame Stones

precious stones — Wed, 16 Sep 2009 15:03:40 +0000

Brown and Flame-Coloured Stones

Hardness. Specific Gravity.

AndalusiteÂ Â Â Â 7-1/2 3.204 Diamond 10 3.502-3.564 Garnets (various) 6-1/2-7-1/2 3.40-4.50 Hyacinth (a form of Zircon), 7-1/2 4.70-4.88 Quartz (smoke coloured) 7 2.670 Tourmaline 7-1/4 3.100 Zircon (Hyacinth) 7-1/2 4.70-4.88

Yellow Stones

precious stones — Wed, 16 Sep 2009 15:02:53 +0000

Yellow Stones

Hardness. Specific Gravity.

Amber 2-1/2 1.000 Beryl 7-3/4 2.709-2.810 Chrysoberyl 8-1/2 3.689-3.752 Chrysolite 6-7 3.316-3.528 Corundum (the yellow variety known as “Oriental Topaz”) 9 3.90-4.16 Diamond 10 3.502-3.564 Garnets (various) 6-1/2-7-1/2 3.4-4.5 Hyacinth (a form of Zircon) 7-1/2 4.7-4.88 Quartz (Citrine) 7 2.658 Sapphire 9 4.049-4.060 Spinel 8 .614-3.654 Topaz (for “Oriental [...]

White or colourless stones

precious stones — Wed, 16 Sep 2009 14:58:08 +0000

White or colourless stones

Hardness. Specific Gravity.

Beryl 7-3/4 2.709-2.81 Corundum 9 3.90-4.16 Diamond 10 3.502-3.564 Jade 7 3.300-3.381 Opal 5-1/2-6-1/2 2.160-2.283 Phenakite 7-3/4 2.965 Quartz 7 2.670 Rock-crystal 7 2.521-2.795 Sapphire 9 4.049-4.060 Spinel 8 3.614-3.654 Topaz 8 3.500-3.520 Tourmaline 7-1/4 3.029 Zircon 7-1/2 4.700-4.880

Testing precious stones

precious stones — Wed, 16 Sep 2009 14:53:23 +0000

We now arrive at the point where it is necessary to discuss the manufacture and re-formation of precious stones, and also to consider a few of the tests which may be applied to all stones. These are given here in order to save needless repetition; the tests which are specially applicable to individual stones will [...]