The specific weight / the specific gravity
The specific gravity
The specific weight, sometimes called "gravity" or
"density" is the ratio of the weight of a body to that of an equal
volume of water. The specific weight of the emerald being 2.71, this means that
it weighs 2.71 times more than the same volume of water (the water density
being 1.0).
The main method used to determine the specific gravity of
liquids is dense. It consists of immersing a stone in a liquid of known
density. The stone will remain suspended in a liquid of equal density, float on
the surface of a liquid denser and sink in a liquid of lesser density. Thus,
the emerald (2.71) will rise to the surface of a liquid whose density is 2.80,
remain in suspension in another with a density of 2.70, and sink slowly into a
liquid whose density is 2.60.
The liquid most commonly used to determine the specific
gravity is bromophorme (2.90), methylene iodide (3.33) and Clerici liquor
(4.15). These liquids can be diluted to lower density and to determine the
specific weight of just about any gemstone that.
Specific gravity of gems and minerals
|
Gem / Mineral
|
Weight
|
|
Agate
|
2.60 -2.65
|
|
Aquamarine
|
2.67 -2.71
|
|
Alexandrite
|
3.70 -3.73
|
|
Almandine
|
4.5
|
|
Amazonite
|
2.56 -2.58
|
|
Amber
|
8.1
|
|
Amethyst
|
2.63 -2.65
|
|
Andalusite
|
3.12 -3.18
|
|
Apatite
|
3.21
|
|
Aventurine
|
2.62 -2.65
|
|
Azurite
|
3.80
|
|
Bénitoite
|
3.67
|
|
Brazilianite
|
2.99
|
|
Chalcedony
|
2.60
|
|
Calcite
|
2.71
|
|
Chrysoberyl
|
3.71
|
|
Chrysocolla
|
2.20
|
|
Chrysopraze
|
2.58 -2.64
|
|
Citrine
|
2.65
|
|
Corundum
|
3.96 -4.01
|
|
Danburite
|
3.00 -3.07
|
|
Demantoid
|
3.82 -3.85
|
|
Diamond
|
3.52
|
|
Diopside
|
3.29
|
|
Dioptase
|
3.30
|
|
Dolomite
|
2.85 -2.95
|
|
Dumortierite
|
3.26 -3.41
|
|
Emerald
|
2.71
|
|
Epidote
|
3.45
|
|
Euclase
|
3.10
|
|
Fluorite
|
3.18
|
|
Gaylussite
|
1.99
|
|
Grossular
|
3.50
|
|
Hauynite
|
2.4
|
|
Hematite
|
5.5
|
|
Hessonite
|
3.65
|
|
Iolite
|
2.59
|
|
Jadeite
|
3.34
|
|
Kornerupine
|
3.32
|
|
Kunzite
|
3.16 -3.2
|
|
Labradorite
|
2.69
|
|
Lapis lazuli
|
2.80
|
|
Lazulite
|
3.9
|
|
Malachite
|
3.80
|
|
Moldavite
|
2.35
|
|
Nephritis
|
2.96
|
|
Obsidian
|
2.3 -2.6
|
|
Onyx
|
2.70
|
|
Opal
|
2.10
|
|
Orthoclase
|
2.56
|
|
Peridot
|
3.34
|
|
Pyrite
|
5.10
|
|
Pyrope
|
3.70
|
|
Quartz
|
2.65
|
|
Rhodochsite
|
3.60
|
|
Rhodonite
|
3.60
|
|
Ruby
|
3.97-4.08
|
|
Sapphire
|
3.99 -4.00
|
|
Scapolite
|
2.70
|
|
Serpentine
|
2.4 -2.8
|
|
Sodalite
|
2.13 -2.29
|
|
Spessartine
|
4.16
|
|
Sphene
|
3.53
|
|
Spinel
|
3.60
|
|
Spodumene
|
3.18
|
|
Taafféite
|
3.61
|
|
Tanzanite
|
3.28 -3.35
|
|
Topaz
|
3.53
|
|
Tourmaline
|
3.02 -3.26
|
|
Turquoise
|
2.80
|
|
Uvarovite
|
3.77
|
|
Variscite
|
2.55
|
|
Glass
|
2.21-4.20
|
|
YAG
|
4.60
|
|
Zoisite
|
3.34
|
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