Mineral Family: Phyllosilicates

Chemical Composition: Ca2Al2Si3O10(OH)2
Cleavage: Good
Color: Yellow-green, brown-yellow
Crystal System: Orthorhombic
Form/Habit: Tabular, botryoidal masses
Fracture: Uneven
Gravity:  2.82-2.94
Hardness: 6- 6.5
Luminescence: Yellowish-white (long wave) / Blueish-white (short wave)
Luster: Vitreous to pearly
Streak: White
Transparency: Transparent, translucent

Where does Prehnite come from?

Prehnite Placeholder

Prehnite deposits are located in Austria, Canada, India, Italy, Mali, Morocco, Namibia, Spain, Tanzania and the United States.

What is Prehnite?

Prehnite is a carbonate Copper Silcate mineral. Silicate minerals are the largest family of minerals, including more than 25% of all known minerals and 40% of all common minerals. In addition to being a major part of the Earth’s crust, Silicate minerals have also been found on the moon and in meteorites. Silicates are minerals which contain the elements Silicon (a light gray shiny metal) and Oxygen (a colorless gas). Together, these two elements form a tetrahedron – a shape similar to a pyramid – with a Silicon atom in the center and Oxygen atoms at each of the four corners. These tetrahedra connect with other chemical structures, in six different ways, to form various minerals and rocks. There are six main groups of Silicate minerals, and these main groups are further subdivided into secondary subdivisions, such as Quartz and Feldspar. Prehnite belongs to the Phyllosilicate group, whose tetrahedra connect at three corners to form hexagonal rings. This group also includes such well-known minerals as Chrysocolla, Fuchsite, Lepidolite, Prehnite, Seraphinite, and Serpentine.

How is Prehnite formed?

Prehnite typically forms in the cavities of volcanic rocks associated with zeolites and calcite and in the mineral veins in granite

How is Prehnite mined?

Prehnite is sometimes mined as a secondary mineral in Granite mines.

Is Prehnite natural?

All Prehnites are natural, enhanced only by cutting or polishing.