1, amethyst is composed of silica, with hardness of 7, specific gravity of 2.65, refractive index of 1.54- 1.55, and dichroism. Viewed from different angles, it can display blue or red-purple tones, and usually consists of mixed or stepped facets. Natural amethyst is beautiful purple because of its iron, manganese and other minerals. The main colors are lavender, fuchsia, crimson, scarlet, deep purple, blue purple and so on, with deep purple and scarlet being the best, and excessive lavender is more common.
Natural amethyst usually has natural ice cracks or white cloud impurities. Amethyst with gem value is produced in volcanic rocks, pegmatites or crystal caves of limestone and shale. Amethyst is widely distributed in nature, mainly produced in Brazil, Russia, South Africa and Madagascar.
2. Fluorite is also called fluorite. Purple fluorite is also called purple ghost. The main chemical component is CaF2, which is the most important fluorine-containing mineral. There are yellow, lavender, rose, green, black, gray and other colors, and sometimes colorless. A dense, massive body. Fragile, transparent, with glass luster and remarkable fluorescence phenomenon. The density is 3.0 1 ~ 3.25g/cm3 and the melting temperature is about 935℃.
3.sugilite, the scientific name of sodium lithium mushroom stone, is mainly composed of Sugilite. In A.D. 1960, a Japanese geologist discovered a new kind of ore. At present, this kind of ore is only produced in China, South Africa, Japan, Canada and the United States. Shuqulaite is composed of potassium, sodium, iron, lithium and other mineral elements. But its basic element combination is silicon oxide.
4. Chaloyi Tezhu, also translated as "Chaloyi Stone", is nicknamed "Purple Prince Stone" by Tibetan friends because of its noble temperament and rarity. High-quality Zi Long crystal contains only purple and white, and white silk is distributed between purple, excluding green, black and other variegated colors. The purple dragon crystal grain is clear and smooth, the whole is uniform and harmonious, and the white mercerization is naturally distributed, giving people different aesthetic feelings from different angles.
Cordierite is a silicate mineral, usually light blue or light purple, glassy, transparent to translucent? [2]。 Cordierite has another feature, which is obviously polychromatic (tricolor) and emits different colors of light in different directions. Cordierite is regarded as a gem because of its excellent quality and bright color. In addition, cordierite is widely used as honeycomb carrier material for automobile purifiers because of its good fire resistance and low thermal expansion rate. Cordierite exists in schist, gneiss and altered igneous rocks. Therefore, people also call cordierite dichroism. Magnesium cordierite can be artificially synthesized and used in refractories. Cordierite rough stones generally weigh 4-5 carats, and larger ones are also found. Cordierite is usually cut into traditional shapes, and the most popular color is blue and purple.
Data expansion:
(1) The largest and most flawless faceted amethyst in the world, with the size of 7 1.5mm×58.5mm×46.3mm, cut into faceted water droplets. Weight 1030 carat, Sri Lanka origin, deep purple with pink tone, rich in color saturation. Standard cutting and grinding ratio, extremely pure inside. This gem is by far the largest and most perfect faceted amethyst in the world and a rare crystal in the world.
(2) Fluorite in nature often presents bright colors, some of which can emit fluorescence. Mohs hardness 4, lower than steel, easy to scratch, brittle, sweet, astringent and non-toxic. Melting point: 1270- 1350℃. Density: 3. 18g/cm? Refractive index: 1.434.
(Source: Baidu Encyclopedia: Amethyst; Baidu encyclopedia: fluorite)