Here at Voltaire Diamonds we hear lots about gemstone durability on a daily basis, much of which is incorrect and or subject to rumour. Here we look at the basics of gemstone durability and debunk some common myths.
Gemstone durability can be defined as a stone’s ability to withstand wear, heat, light, household chemicals, and low or high humidity. As most gemstones have different properties they also have varying tolerances to each stressor. With this in mind, gem specialists evaluate the durability of a gemstone upon the following 3 core factors: 1) hardness, 2) toughness, and 3) stability.
1). Gemstone Hardness
This is a gemstone’s ability to resist scrathes and abrasion. The Mohs scale assigns gemtones a number according to their hardness. The Mohs scale of mineral hardness is based on the ability of one natural sample of mineral to scratch another mineral visibly. This is an ordinal scale, for example sapphire is 9, while diamond, despite being four times harder is 10 on the scale.
2). Gemstone Toughness
This is measured as a gemstone’s ability to resist breaking and chipping or simply put a gemstone’s ability to withstand bumps and knocks. Contrary to common thought, diamond is not the toughest gemstone. Diamonds can chip and break from mechanical shock as can most other gemstones. Emeralds, tanzanite, opal and topaz are all prone to chipping or fracture. Jadeite/Jade may look soft however it is the toughest of all the gemstones. Indeed Jadeite has been employed for thousands of years as weapons, and tools for scraping and hammering because of it’s toughness.
3). Gemstone Stability
This refers to the ability of a gemstone to resist chemicals, heat, humidity and light. Diamonds are generally very stable however they can be affected by thermal shock. Sudden extreme changes in temperature can cause fractures and exacerbate existing inclusions. Sudden changes in temperature can also damage gems such as apatite, iolite, kunzite, opal, and tanzanite. Sometimes gemstones can turn cloudy or can even turn a different colour. Prolonged exposure to heat and light can damage many gemstones and exposure to chemicals can discolour delicate gems.
Always listen to the advice of an experienced jeweller and get your valuables serviced regularly. Gemstones have been adored for their beauty and durability for thousands upon thousands of years. Knowing their unique properties and caring for them regularly will ensure that you can treasure your jewellery for many years to come.