🔍 Quartz is a violet variety of quartz, whose crystals form inside basaltic rock geodes.'
Chemical formula : SiO2
Hardness (Mohs): 7
Crystalline System : Trigonal
Luster: Vitreous
⏳ The name amethyst derives from the Greek “𝘢𝘮𝘦𝘵𝘩𝘺𝘴𝘵𝘰𝘴”, which literally means “𝘯𝘰𝘯 𝘦𝘣𝘣𝘳𝘰”, as the ancient Greeks believed that it was an excellent remedy against intoxications. Even the ancient Romans nurtured this belief; while medieval knights wore amethyst amulets into battle as a symbol of protection.
⛰️ The first findings of amethyst jewels date back to the times of Ancient Egypt, there will then be numerous applications and meanings attributed to this mineral over the years.
The Ancient Greeks used amethyst to prevent poisoning, while medieval soldiers wore amethyst amulets into battle as a symbol of protection.
🧪 The purple color is due to the presence of trivalent iron ions in the quartz crystalline lattice and ionic radiation. The irradiations cause Fe 3+ to replace Si 4+ in the SiO4 tetrahedron, causing an imbalance of the electrical charges neutralized by the presence of a positive monovalent ion nearby. The color center is therefore due to the formation of [FeO4]º/ [Fe Si O4/h+]º.
Amethyst crystals are essentially found inside geodes developed in basaltic rocks. Geodes are cavities present within igneous rocks, which represent, in fact, gas bubbles variously modeled by the greater or lesser flow of the magmatic liquid. The lower the viscosity of the liquid, the more elongated the shape of the geode can be, of which the sharpest part coincides with the direction of flow. On the internal walls of these geodes, groupings of crystals can develop (among the most common quartz, zeolites, carbonates and sulphates) "grown" thanks to the particular chemical composition and the relatively high temperature (from 850 to 50 °C) of the percolated hydrothermal fluids through the rock.
🌎 The main amethyst deposits are found in Brazil, Uruguay, Bolivia, India, Russia, Mexico, USA and Madagascar; in Italy there are some small deposits in some regions of the North and in Sardinia.
