From the published encyclopedia
Read the care sections of our published gemstone references. Each excerpt links to the complete article and its recorded sources.
Corundum rates 9 on the Mohs scale. Hardness concerns resistance to scratching; it is not a guarantee against every kind of damage. GIA recommends a damp cloth for fracture-filled, cavity-filled or dyed ruby. Do not choose ultrasonic or steam cleaning without knowing the stone’s treatment and condition.
Read the full reference and sources →Sapphire rates 9 on the Mohs scale. GIA distinguishes the care of untreated or heated sapphire from filled or dyed material. When the treatment or condition is uncertain, seek stone-specific instructions before using an ultrasonic or steam cleaner. Store it so that it cannot rub against other jewellery.
Read the full reference and sources →As corundum, sapphire rates 9 on the Mohs scale. A high hardness number should not be read as permission to use every cleaning method. Filled or dyed sapphire requires special care, and a setting may introduce additional cleaning restrictions. Ask for instructions that address both the stone and its disclosed condition.
Read the full reference and sources →Emerald rates 7.5 to 8 on the Mohs scale. GIA warns that heat, chemicals, ultrasonic vibration and steam can create problems for fractured or filled stones. Gentle cleaning with warm soapy water is the safer general approach described in its guide. Obtain specific advice for the condition and treatment of an individual emerald.
Read the full reference and sources →Aquamarine rates 7.5 to 8 on the Mohs scale. Protect it from scratching and knocks. GIA recommends warm soapy water as a safe general cleaning method and advises against heat exposure. Ultrasonic or steam cleaning should not be selected without considering fractures, inclusions and any disclosed treatment.
Read the full reference and sources →Examine visible inclusions and setting protection rather than assuming all beryl needs identical care. Store jewellery separately to reduce abrasion.
Read the full reference and sources →Keep prolonged intense light and heat out of the storage environment; ask for care advice that reflects any treatment.
Read the full reference and sources →Request a written colour-treatment description, especially when comparing a pale yellow stone with strongly orange material.
Read the full reference and sources →Protect cabochon surfaces and avoid ultrasonic and steam cleaning. Inspect the setting and any fractures before adopting a cleaning routine.
Read the full reference and sources →Ask about the identified feldspar, treatment and condition. Protect the surface from impacts and seek cleaning advice for included or fractured stones.
Read the full reference and sources →Ask for comparable views under stated lighting and an appropriate identification report. Do not infer geographic origin or treatment from the strength of the change.
Read the full reference and sources →Keep acids, aggressive chemicals and heat away. Ask about dye, wax and other surface treatments before cleaning a carving or bead strand.
Read the full reference and sources →Protect against cosmetics, chemicals and heat. Obtain treatment details before cleaning and avoid assuming all turquoise can be immersed safely.
Read the full reference and sources →Read the report scope and comments, and check how the report is matched to the stone. A grading report for another diamond is not transferable evidence.
Read the full reference and sources →Assess the actual stone for fractures and treatment before cleaning. A family name alone cannot describe its condition.
Read the full reference and sources →Cleavage and sensitivity to sudden temperature changes matter when setting and cleaning. Seek specific advice before using mechanical cleaners.
Read the full reference and sources →Protect facet edges from abrasion and knocks. Ask the seller for a clear material name rather than an abbreviation that could be confused with CZ.
Read the full reference and sources →Topaz has cleavage. Its Mohs hardness does not remove the risk of splitting after a blow; discuss protective settings and cleaning with a professional.
Read the full reference and sources →Protect exposed edges from knocks and avoid acids and abrupt temperature changes. Do not use a scratch test on a finished gem.
Read the full reference and sources →Protect from heat, chemicals and abrasion. Do not use a hot needle, flame, solvent or other damaging home test on a specimen.
Read the full reference and sources →Ask which species or variety is being described. Compare colour, inclusions and cut for the individual gem, with treatment and condition recorded.
Read the full reference and sources →Heat, filling and other enhancement questions require disclosure for the particular stone. Avoid equating a vivid photograph with a complete report.
Read the full reference and sources →Avoid heat and sudden environmental changes. Ask about water sensitivity and any impregnation or assembled construction before choosing a cleaning method.
Read the full reference and sources →Avoid applying one hardness or cleaning rule to all jade objects. Surface treatments and assembled pieces need individual assessment.
Read the full reference and sources →Use a soft damp cloth, protect from cosmetics and store separately from harder gems. Check stringing and fittings regularly; ask for advice about treated pearls.
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