Heavy Liquid Method - Specific Gravity

Specific Gravity

Specific gravity is a measurement used in the heavy liquid method to determine the density of minerals. It is the ratio of the density of a substance to the density of a reference substance (usually water). Specific gravity is a dimensionless quantity.

In the heavy liquid method, specific gravity is used to determine the appropriate heavy liquid to use for mineral separation. Each heavy liquid has a specific gravity that allows it to separate minerals based on their density.

Types of Liquids and Their Uses

• Tetrabromoethane (TBE): Used for separating minerals with a density greater than 2.85 g/cm³.
• Sodium polytungstate (SPT): Used for separating minerals with a density between 2.85 g/cm³ and 2.95 g/cm³.
• Diiodomethane (DIM): Used for separating minerals with a density less than 2.95 g/cm³.

Precautions

• Handle the heavy liquids in a well-ventilated area or under a fume hood to avoid inhaling any fumes.
• Wear appropriate personal protective equipment, such as gloves and goggles, to protect yourself from the heavy liquids.
• Store the heavy liquids in properly labeled containers and away from sources of heat or ignition.
• Dispose of the used heavy liquids according to local regulations and guidelines.

Further reading

Standard Gemological Instruments and their use