Knowledge
Caring for valuable gemstones
Proper care depends on the stone: its hardness, its toughness and any treatment. What helps, what harms and when to consult a professional.
Gemstones are durable, but not indestructible. How a stone should be cared for depends on its material properties, its inclusions, any treatment and its setting. There is no single rule for all.
What determines care
- Hardness: diamond (10), ruby and sapphire (9) are very scratch-resistant; emerald (7.5–8) and tourmaline (7–7.5) less so
- Toughness and cleavage: stones with pronounced cleavage can chip when struck
- Inclusions and fractures: they weaken the stone in particular areas
- Treatment: fillings of oil, resin or glass react to heat, solvents and ultrasound
Cleaning
For most stones, lukewarm water with a little mild soap and a soft brush is enough. Rinse well afterwards and dry with a lint-free cloth. Ultrasonic and steam cleaners are usually unproblematic for diamonds and untreated rubies and sapphires, but risky for emeralds and for filled or heavily included stones. If in doubt, avoid them.
Storage
Store stones separately so that harder stones do not scratch softer ones. Diamonds can even scratch other diamonds. A soft case with compartments or separate pouches is ideal.
Wearing
Remove jewellery for sport, gardening or when handling chemicals. Cosmetics, perfume and chlorine can attack surfaces and settings. Rings are exposed to more wear than earrings or pendants.
When to consult a professional
Have settings checked regularly, for example once a year. Before any repair, resetting or professional cleaning, give the goldsmith the laboratory report and the treatment, because the heat of soldering can damage fillings or stones with inclusions.
Stones held in a bonded warehouse
A stone kept in a high-security vault is protected from wear. The question of care only arises once it is delivered and set.
In brief
Care depends on hardness, toughness, inclusions and treatment. Mild soapy water is enough for most stones; ultrasound and steam are only suitable for robust, untreated stones. Whenever work is done on the piece, give the goldsmith the report and the treatment.
At NOBILITH
The dossier contains the treatment and laboratory observations relevant to care. When a stone is released from custody, care guidance for that species is included.
Sources
- GIA: Gem Encyclopedia, care and cleaning
- CIBJO: The Gemstone Book, durability
Read more
- Laboratory reportsUnderstanding a laboratory reportA laboratory report is a gemstone's most important document. Which information it contains, how to read it and what it does not say.Read more
- Gem LabGemmological microscopeThe most important instrument in the laboratory: under the microscope, inclusions, growth features and signs of treatment become visible.Read more
- KnowledgeHow to read a gemstone dossierA dossier brings together everything that describes a stone – from the laboratory report to custody. Here is how to read it in the right order.Read more
- KnowledgeNatural, synthetic and imitation materialThree terms that are often confused: what they mean, how a laboratory tells them apart and why the classification must never rest on assumption.Read more
Updated 2026-10-06