THE SHORT ANSWER
Specific gravity tests average the object; they do not identify every interior
A hydrostatic specific-gravity test relates measured mass to displaced volume, usually by comparing a dry weighing with an immersed observation under a documented liquid and temperature. This can expose a gross mismatch between an object and the expected alloy or product. It cannot prove authenticity: geometry, bubbles, attachments, voids, mixed construction and measurement resolution affect the result, and tungsten's density is close enough to gold that a density match cannot exclude it.
HYDROSTATIC MEASUREMENT WORKSHEET
Calculate density from dry and immersed mass
Enter the apparent immersed mass after taring the suspension setup. The tool interpolates a water-density reference between 15–30 °C and propagates one-half display step from both weighings into a resolution-only interval.
Do not treat a close number as a pass. Air bubbles, surface tension, vessel contact, porous or hollow construction, stones, attachments, alloy composition and similar-density substitutions can dominate the calculation. Gold and tungsten have similar densities; use product specifications and appropriate surface/interior or laboratory evidence.
METHOD BOUNDARY
Separate the observation from the conclusion
MEASUREMENT MODEL
Show the observations before the derived ratio
UNCERTAINTY
A decimal-rich answer can still be weak evidence
The derived ratio inherits uncertainty from both weighings and the liquid model. Small coins, thin jewelry and items with limited immersed-mass difference demand more from scale resolution. A bubble or water bridge can shift the result more than the difference being investigated. Repeat observations and a suitable control can reveal instability, but repetitions do not fix a biased setup.
Compare against the composition of the exact product. A one-ounce American Gold Eagle is a 22-karat alloy with a gross weight above one troy ounce; a Gold Buffalo is .9999 fine and has a different composition. Official product facts must precede the density conclusion.
PRIMARY AND STANDARDS SOURCES
Methods are only as strong as their scope and controls
- LBMA Physical Market Guidelines distinguish surface XRF, ultrasound, eddy current and representative destructive analysis. LBMA states that no definitive non-destructive solution is currently endorsed.
- NISTIR 5078 water-property tables provide the water-density reference basis used by the calculator's documented 15–30 °C interpolation.
- LBMA's density of gold explainer gives the 19.32 g/cm³ room-temperature pure-gold reference and shows why alloying and temperature change density.
- U.S. Mint bullion consumer awareness and official bullion specifications provide product-specific mass and dimension references for U.S. bullion coins. They do not make a home measurement conclusive.
Sources reviewed July 31, 2026. Instrument procedures, safety data, standards and acceptance criteria can change. Use the current method documentation for the exact item, instrument, laboratory and decision.
FREQUENTLY ASKED QUESTIONS
Gold specific-gravity questions
How do you calculate the specific gravity of gold?
A common hydrostatic approach compares mass in air with apparent mass while fully immersed in a liquid of known density. The exact equation and corrections depend on the setup and method.
Is pure gold always 19.32 specific gravity?
Published reference values are temperature- and material-dependent, and real bullion alloys are not pure gold. Do not compare a 22-karat coin or mixed object to a pure-gold number.
Can tungsten pass a gold density test?
Gold and tungsten have similar densities, which is precisely why density alone cannot exclude a tungsten substitution or every composite construction.
Why is my gold density result wrong?
Air bubbles, surface tension, incomplete immersion, touching the vessel, attachments, cavities, porous or hollow construction, liquid temperature, scale resolution and the wrong product reference can all matter.