Description

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.

Epidote is an abundant rock-forming mineral, but one of the secondary origin. Many of the characters of the mineral vary with the amount of iron present. Prismatic, columnar crystals, often shiny, finely striated faces. The color is green, gray, brown or nearly black but usually a characteristic shade of yellowish-green or pistachio green.

Feldspars are a group of rock-forming tectosilicate group of minerals containing potassium, sodium, calcium and aluminium silicatesminerals that make up as much as 60% of the Earth’s crust.  They are the most common rock-forming minerals. Feldspars crystallize from magma as veins in both intrusive and extrusive igneous rocks and are also present in many types of metamorphic rock. Feldspars are also found in many types of sedimentary rock.