Specific gravity is the ratio of the density of a substance to the density of a reference substance. The Specific gravity of a gemstone is the ratio of the density of the gemstone to the density of water. In other words it's the ratio of the weight of a volume of the gemstone to the weight of an equal volume of water.
The specific gravity for each gamestone is indicated in the Gemstones hardness chart.
The specific gravity for each gamestone is indicated in the Gemstones hardness chart.
Note: The reverence substance for gases is air.
