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General gem care

Normal gemstone care means avoiding rough handling, storing pieces separately and cleaning with warm soapy water and gentle brushing. This page quotes the CIBJO wording for normal care and for special-care codes a to n. Under each code, the page lists the materials on this site that cite that code.

On this page

Normal care for all gemstones

With all gemstones avoid rough handling and when not in wear, keep items of jewellery separate to avoid scratches. Clean with warm soapy water and gentle brushing. Ultrasonic cleaners should only be used with caution.

Source
CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §6.1 (Annex A, care requirements), p.29

§6.2 special-care codes (a–n)

On top of normal care, the source lists special-care requirements for some gemstones, one letter each; the care notes on individual gemstone entries cite these letters.

a

Some stones are prone to scratching due to low hardness. Wear them with care.

§6.2 a (Annex A, care requirements), p.29

Materials on this site that cite this code

b

Some stones cleave or fracture easily or are prone to the effects of brittleness e.g. rubbed facet edges. Wear them with care.

§6.2 b (Annex A, care requirements), p.29

Materials on this site that cite this code

c

Some stones are porous. Do not allow contact with coloured fluids.

§6.2 c (Annex A, care requirements), p.29

Materials on this site that cite this code

d

Some stones are prone to crack due to loss of structural water. Keep away from heat and drying environments.

§6.2 d (Annex A, care requirements), p.29

Materials on this site that cite this code

e

Some stones are prone to damage due to thermal shock. Do not expose them to extreme temperature changes.

§6.2 e (Annex A, care requirements), p.29

Materials on this site that cite this code

f

Some stones fade or revert to original colour when exposed to strong light. Do not wear or leave them for extended periods under these conditions.

§6.2 f (Annex A, care requirements), p.29

Materials on this site that cite this code

g

Some stones fade rapidly unless kept in the dark.

§6.2 g (Annex A, care requirements), p.29

Materials on this site that cite this code

h

Some stones are particularly susceptible to attack by acids. Keep them away from acids.

§6.2 h (Annex A, care requirements), p.29

Materials on this site that cite this code

i

Some organic substances dissolve upon contact with solvents such as nail varnish remover. Keep them away from all solvents and other strong chemicals.

§6.2 i (Annex A, care requirements), p.29–30

Materials on this site that cite this code

j

Some stones are susceptible to damage from ultrasonic cleaning. Do not expose them to ultrasonic cleaning.

§6.2 j (Annex A, care requirements), p.30

Materials on this site that cite this code

k

Stones treated with dye, oil, resin, wax, or plastic are not permanent. Keep away from all solvents (including various dish-washing liquids), chemicals and heat.

§6.2 k (Annex A, care requirements), p.30

Materials on this site that cite this code

Treatments this code names: Dyed, Filled / Fracture-filled, Waxed, Impregnated

l

Fillers in voids/cavities, fissures, and/or open fractures, such as glass, plastic or hardened resin, can scratch more easily than the host stone or be more vulnerable to damage from heat or some acids (e.g. hydrofluoric). Keep away from all chemicals, heat or abrasives.

§6.2 l (Annex A, care requirements), p.30

Materials on this site that cite this code

Treatments this code names: Filled / Fracture-filled

m

Stones with superficial colour and surface layers are not suitable for re-cutting or re-polishing.

§6.2 m (Annex A, care requirements), p.30

Materials on this site that cite this code

n

Coatings on stones are often easily removed by the action of solvents, heat or abrasives. Keep away from all solvents, heat or abrasives. Coated stones are not suitable for re-cutting or re-polishing.

§6.2 n (Annex A, care requirements), p.30

Materials on this site that cite this code

Treatments this code names: Coated

CIBJO Coral Book §6.2 special-care codes (a–k)

The CIBJO Coral Book has its own special-care code table. Its letters mean different things from the Gemstone Book letters above and are not interchangeable; the care notes on coral entries cite this table.

a

Corals are prone to scratching due to low hardness. Wear them with care.

§6.2 a (Annex A, coral care requirements), p.22

Materials on this site that cite this code

b

Corals are porous. Do not allow contact with coloured fluids.

§6.2 b (Annex A, coral care requirements), p.22

Materials on this site that cite this code

c

Corals are prone to crack due to loss of structural water. Keep away from heat and drying environments.

§6.2 c (Annex A, coral care requirements), p.22

Materials on this site that cite this code

d

Corals are prone to damage due to thermal shock. Do not expose them to extreme temperature changes.

§6.2 d (Annex A, coral care requirements), p.22

Materials on this site that cite this code

e

Corals fade or revert to original colour when exposed to strong light. Do not wear or leave them for extended periods under these conditions.

§6.2 e (Annex A, coral care requirements), p.22

Materials on this site that cite this code

f

Corals dissolve upon contact with acids and solvents (such as nail varnish remover). Keep them away from all solvents and other strong chemicals.

§6.2 f (Annex A, coral care requirements), p.22

Materials on this site that cite this code

g

Corals are particularly susceptible to damage from ultrasonic cleaning. Do not expose them to ultrasonic cleaning.

§6.2 g (Annex A, coral care requirements), p.22

Materials on this site that cite this code

h

Modifications to corals with dye, oil, resin, wax, or plastic are not permanent. Keep away from all solvents (including various dish-washing liquids), chemicals and heat.

§6.2 h (Annex A, coral care requirements), p.22

Materials on this site that cite this code

i

Coral with superficial colour and surface layers are not suitable for re-cutting or re-polishing.

§6.2 i (Annex A, coral care requirements), p.22

Materials on this site that cite this code

j

As a biogenic gem, coral must be kept in a condition that is not too dry and not too humid.

§6.2 j (Annex A, coral care requirements), p.22–23

Materials on this site that cite this code

k

Coatings on coral are often easily removed by the action of solvents, heat or abrasives, which are generally harmful to the coral. Keep away from all solvents, heat or abrasives. Coated coral is not suitable for re-cutting or re-polishing.

§6.2 k (Annex A, coral care requirements), p.23

Materials on this site that cite this code

Entries by care aspect

Each gemstone entry records its care notes under the aspects below; each list links to the entries that have a note on that aspect.

Cleaning

Chemicals

Heat

Light

Storage

Wear

Setting

Display

Repair

Re-cutting

Special care