Destructive Gemstone Tests: Acid Testing

Step 3: Practical Gemology

Lesson 22

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Acid testing can be used to determine if a piece of lapis lazuli is real or an imitation. Real lapis lazuli will release a smell like rotten eggs and effervesce. Acid testing is a destructive test and must be done with safety precautions for both the test piece and the gemologist. “Second-lapis-tbs-crystals-side1” by nimbus186 is licensed under CC By-SA 2.0
Acid testing can be used to determine if a piece of lapis lazuli is real or an imitation. Real lapis lazuli will release a smell like rotten eggs and effervesce. Acid testing is a destructive test and must be done with safety precautions for both the test piece and the gemologist. “Second-lapis-tbs-crystals-side1” by nimbus186 is licensed under CC By-SA 2.0

In some cases, a hot point test will not distinguish plastic simulants or imitations from natural gems. Some plastics release a protein smell when hot point tested, just like their natural counterparts. Natural coral, shell, and pearl release a protein smell. These organic gem materials are carbonates, just like malachite and rhodochrosite. You can make a positive identification of these gem specimens through acid testing, examining how they react to acid.

Acid Testing Warnings

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