What term is defined as the ratio of the weight of a material to that of an equal volume of water?

What term is defined as the ratio of the weight of a material to that of an equal volume of water?

• A. Subduction
• B. Star facet length percentage
• C. Splitter
• D. Specific gravity (SG)

Answer: (D)

Specific gravity is a measure of how heavy a material is relative to an equal volume of water. It’s defined as the ratio of the material’s weight to the weight of the same volume of water, so it’s a dimensionless value. Because water at 4°C has a density of 1 g/cm³, specific gravity essentially equals the material’s density in g/cm³. In gemology, this helps identify stones because different minerals have characteristic densities (for example, diamonds around 3.52). The value is determined by weighing the stone in air and then in water (or another liquid), using SG = weight in air divided by (weight in air minus weight in water). The other terms listed refer to processes or concepts not about comparing weight to water, so they don’t describe this ratio.

Specific gravity is a measure of how heavy a material is relative to an equal volume of water. It’s defined as the ratio of the material’s weight to the weight of the same volume of water, so it’s a dimensionless value. Because water at 4°C has a density of 1 g/cm³, specific gravity essentially equals the material’s density in g/cm³. In gemology, this helps identify stones because different minerals have characteristic densities (for example, diamonds around 3.52). The value is determined by weighing the stone in air and then in water (or another liquid), using SG = weight in air divided by (weight in air minus weight in water). The other terms listed refer to processes or concepts not about comparing weight to water, so they don’t describe this ratio.