Phacolite
Phacolite (also spelled phakolith or phacolit) is not a distinct mineral species, but rather a lens-shaped variety of the zeolite mineral chabazite formed by complex twinning. The name is derived from the Greek word phakos, meaning "lens", and describes its characteristic crystal habit. The first description of phacolite was made in the early 19th century by Johann Friedrich August Breithaupt (1791–1873), based on specimens found in Northern Bohemia. Breithaupt sourced his original type material specifically from basalt outcrops near Böhmisch Leipa (Česká Lípa). Since phacolite structurally belongs to the chabazite group (framework silicates / zeolites), it shares its chemical and physical properties. The typical appearance of phacolite differs significantly from the otherwise rather cube-like (rhombohedral) crystals of normal chabazite: multiple, complex twinning of rhombohedrons results in seemingly lens-shaped, often rounded crystals. The faces frequently display a characteristic striation resembling the corners of picture frames, as well as seemingly curved surfaces. Colorless, milky-white to yellowish crystal aggregates that are transparent to translucent with a distinct vitreous luster are typical of phacolite.
Phacolite
Item-No.: MINS46 Price: 75.00 EUR
Litoměřice area, Ústí nad Laben Region, Czech Republic