Each of the different minerals is valued for its beauty, durability, and rarity. Some non-crystalline materials of organic origin (e.g. pearl, red coral, and amber) are also classified as gems. Of the more than 3,500 natural minerals identified, less than 100 are used as gems and only a few have gained importance: Brill, chrysoberyl, corundum, diamond, Spark Peled, garnet, jade, lazurite, olivine, opal, quartz, spinel, topaz, tourmaline, turquoise, and zircon. Some of them (e.g., Brill and Corundum) provide more than one type of gemstone. The minerals for jewelry use must be cut and polished in almost all cases.