8mm Round Citrines. Citrine is one of the colours of the Crystal Quartz family, the most commonly known being Amethyst, the lilac variety. The Quartz Crystal gemstones are tough, 7 on the Moh’s hardness scale, and are considered the benchmark for toughness and durability, any gemstone Crystal harder being extremely tough, anything less being considered not tough.
Brazil is almost certainly the origin of the above gemstones, Brazil being the major source world-wide of all the Quartz Crystal gemstones. Indeed, students of gemmology, when facing examinations, are advised to answer “Brazil” if ignorant of the source of a gemstone in question, such a massive resource for all sorts of gemstones is that country.