Specific Gravity Tools for Gemstones & Minerals
Use density as one objective property in a multi-test identification workflow. Choose a method that matches specimen size, porosity and measurement precision.
Choose equipment from the material and job first—not from the retailer first.
How do you measure specific gravity of a gemstone?
A common method weighs a specimen in air and in water using a suitable hydrostatic setup. Accuracy depends on scale readability, specimen behavior, bubbles, porosity and technique, so specific gravity should be combined with other identification properties.
Objective evidence that complements appearance.
Specific gravity can eliminate many candidates when measured carefully.
Porosity and trapped bubbles matter.
Hydrostatic methods assume the specimen and measurement setup behave appropriately. Porous material, coatings and tiny stones can increase error.
Specific-gravity measurement options
Specific Gravity Kit for Carat Scale
- Best fit
- Hydrostatic SG measurement using a compatible carat scale
- Capacity/class
- Above-scale underwater weighing kit
- Power
- Uses compatible electronic scale
- Availability
- Typically ships within one business day at source check
- Purpose-built above-scale hydrostatic setup
- Includes holder, beaker, test weight, tweezers and reference table
- Requires a compatible scale with sufficient capacity/readability
- Bubbles, surface tension, porosity and measurement technique can affect results
Direct Reading Specific Gravity Balance
- Best fit
- Dedicated direct-reading SG workflow without improvising a suspended setup
- Capacity/class
- Dedicated SG balance
- Power
- None / mechanical workflow
- Availability
- Current listing active at source check
- Dedicated specific-gravity measurement route
- Avoids using color alone for identification
- SG usually narrows possibilities rather than proving identity
- Porous/coated specimens can undermine hydrostatic assumptions
Mineral Hydrometer
- Best fit
- Specialist density/specific-gravity workflows where a hydrometer-style method is appropriate
- Capacity/class
- Mineral-specific density tool
- Power
- None
- Availability
- Current listing active at source check
- Specialist property measurement option
- Adds another objective property to identification work
- Not a universal replacement for hydrostatic weighing
- Use only when the method fits the specimen and instructions
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- Mineralab specific gravity kit
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