Which term defines the ratio of the weight of a material to that of an equal volume of water?

Which term defines the ratio of the weight of a material to that of an equal volume of water?

• A. Grain lines
• B. Specific gravity
• C. Habit
• D. Trace elements

Answer: (B)

Specific gravity is the ratio of the weight of a material to the weight of an equal volume of water. This makes it a dimensionless comparison of density to water; since water is about 1 g/cm^3, the numerical value of specific gravity closely matches the material’s density in g/cm^3. In practice, denser materials for the same volume have higher specific gravity, which is a useful diagnostic property in gemology and mineralogy. The other terms describe crystal form, growth habits, or impurities rather than a density comparison: grain lines relate to internal features of grains, habit to the crystal’s overall shape, and trace elements to impurities that can affect color or other properties.

Specific gravity is the ratio of the weight of a material to the weight of an equal volume of water. This makes it a dimensionless comparison of density to water; since water is about 1 g/cm^3, the numerical value of specific gravity closely matches the material’s density in g/cm^3. In practice, denser materials for the same volume have higher specific gravity, which is a useful diagnostic property in gemology and mineralogy. The other terms describe crystal form, growth habits, or impurities rather than a density comparison: grain lines relate to internal features of grains, habit to the crystal’s overall shape, and trace elements to impurities that can affect color or other properties.