General stone information
We divide our stone assortment into four main categories, diamonds, gemstones, cultured pearls and man-made stones
In the stone descriptions the following definitions apply:
Gemstone durability is extremely important because it determines what kind of jewellery the gem is suited for, as well as the care with which it must be worn and treated. Gemstone durability is made up of three factors; hardness, toughness and stability.
Hardness is an expression of the ability of a gemstone to resist scratches and abrasion.
The scale commonly used to rate gemstone hardness, was created in 1822 by Friedrich Mohs. He chose ten minerals and assigned numbers to them, based on the relative ease or difficulty with which one could be scratched by another. The scale ranks minerals from one to ten, with ten being the hardest. Each mineral
has the ability to scratch all of the minerals ranking below it on the scale.
It is important to realise, that the scale measures the relative hardness of minerals and numbers indicate position on the scale only. Diamond is just one number
above corundum (sapphire and ruby) on the scale, but is actually many times harder. If the hardness of a gemstone is between two numbers on the scale, it is
expressed by adding “½” to the lowest number.
Toughness is a measure of how well a gemstone resists breaking, chipping or cracking on impact. Any stone, diamond included, will fracture if it is hit hard enough. Toughness is rated as either poor, fair, good, excellent or exceptional.
Another measure of durability is stability. Stability is the tendency of a material to be altered by exposure to light, heat or chemicals. Some gems, such as amethyst, are sensitive to light and can fade if exposed to strong light for long periods.
Gems that contain water such as opals, can become dehydrated and crack.
Sudden temperatures changes can induce thermal shock in some gems leading them to crack or fracture.
Avoid rough handling and when not in wear, keep your jewellery separated to avoid scratches. Clean with warm soapy water and gentle brushing. Ultrasonic cleaners should only be used with caution.
Under each stone is noted if it requires special care in addition to the above.
See the list of stones and other materials used in Pandora jewellery here.
Gem treatment refers to any human-controlled process, except for cutting and polishing, which will improve the appearance, durability or value of a gem. The purpose of gem treatments is mainly to improve gemstone appearance and can be compared to the way other natural materials, such as leather and cotton, are “treated” through procedures such as dyeing.
Pandora wishes to comply with jewellery industry regulations regarding correct marketing and declaration of gemstone treatments. We do so by following the FTC (Federal Trade Commission, USA) guidelines for gemstones and the RJC (Responsible Jewellery Council) guidelines for diamonds. Pandora is a certified member of the RJC (for more information go to CSR)
The FTC states that the following types of treatments must be disclosed to the customer:
- Treatments which are not permanent
- Treatments which create special care requirements
- Treatments which significantly affect the gemstone’s value
Treatment, if any, of individual Pandora gemstones is disclosed in the gemstone description. The main treatments involve modifications with colourless substances or heat to improve gemstone clarity, by heating or bleaching to improve their colour or by surface waxing to improve their polish.
Treatments other than those above are specifically disclosed (by the word treated) unless the result of
treatment is permanent under normal conditions and requires no special care and provided that the treated
stone cannot be visually confused with an untreated counterpart.