In gemology, gems are generally divided into two types: precious stones and semi-precious stones. The main semi-precious stones are: tourmaline, crystal, lapis lazuli, topaz (topaz), aquamarine, garnet, olivine, tiger’s eye (wood change stone), labradorite (moonstone), starstone, Obsidian, malachite, turquoise, red rhodolite, zirconia, dongling jade, fluorite, agate, chalcedony, Czech meteorite, opal, sultanite, hectorite, calcite, etc. In addition, organic gemstones, amber, pearl, and coral are also classified as semi-precious stones.