Gemmology . What is the Mohs scale for gemstones? The Mohs scale is used to identify the hardness of a gemstone, its resistance to scratching, and therefore its suitability for use in jewellery and fine jewellery. The Ultimate Guide to Birthstones for Jewellery Explore the meaning and properties of gemstones with our comprehensive birthstone jewellery guide. Ideal for finding a gift or expressing your individuality! L’ECOLE, The School of Jewelry Arts: free online talks! L’ECOLE Van Cleef & Arpels School of Jewelry Arts is offering free online talks. Diamonds, gemology, dance… 4 webinars you don’t want to miss in March 2021! 10 tips to buy gemstones abroad Our tips for buying gemstones abroad with Patrick Voillot, gemologist and curator of the mineraolgy collection in Paris. Aquamarine, the March birthstone Focus on aquamarine this March. Sailor’s talisman, symbol of fidelity for newlyweds… we tell you everything you need to know about this sea-blue stone. Amethyst, the February birthstone Focus on amethyst this February. Royal stone, Dionysus’s revenge… we tell you everything you need to know about this purple gem. Citrine, the November birthstone Citrine is part of the quartz family, which is rated a 7 on the Mohs hardness scale. Deposits are mainly found in Brazil, Madagascar and Sri Lanka.