Description
Topaz is a silicate mineral of aluminum and fluorine and makes an ideal gem. A good hardness and desirable colors, combined with a relative abundance and availability makes it one the most popular gemstones. Value increases with a deepness of color in orange and reddish hues. Topaz crystallizes in the orthohombic system, and its crystals are mostly prismatic terminated by pyramidal and other faces.
Quartz is the second most common mineral in the Earth’s continental crust. It is mainly composed of Silica or Silica based minerals. Although Quartz is known by a variety of names, the most important distinction between types of Quartz is that of macro-crystalline, individual crystals visible to the unaided eye, and micro-crystalline, where aggregates of crystals are only visible under high magnification. There are many forms of Quartz including Chalcedony, Amethyst, Citrine, and Carnelian which are results of mineral impurities or heat treatments.
Barite gets its name from the Greek word baros (heavy) due to its high specific gravity. Barite is mostly mined as an ore for barium. It can form as crystals or as an aggregate. The mineral is most often white or colorless but can form in array of colors. Crystals are transparent to opaque with prismatic, tabular, bladed, or acicular habits. Aggregates can be massive, granular, concretionary, and fibrous. The crystals are soft and brittle and have perfect cleavage in two directions. Specimens should be kept from heat, and they might fade in sunlight. Specimens might fluoresce and some have greenish white phosphoresce. It is used in the manufacture of paints and paper. Although Barite contains a ‘heavy’ metal, Barium, it is not considered to be a toxic chemical because of its extreme insolubility.
Lepidolite is a lilac-grey or rose-colored member of the Mica group that is a secondary source of Lithium. It is one of the major sources of the rare alkali metals Rubidium and Caesium. Lepidolite occurs in Granite pegmatites, in some high temperature Quartz veins.
