Granitic Pegmatite with Tourmaline and Sphalerite

Physical Properties

Hardness: 6-7.5 (variable); Color: White matrix (quartz/feldspar) with black elongated schorl crystals and green/dark metallic sphalerite; Luster: Vitreous to resinous; Structure: Large, interlocking crystals typical of pegmatitic textures.

Formation & Geological History

Formed during the final stages of a magma chamber's crystallization, where water-rich fluids allow for the growth of massive crystals. These typically date to various Orogenic cycles depending on local geology.

Uses & Applications

Primarily of value to geological collectors and museums; pegmatites are also sources of rare earth elements, lithium, and gemstones.

Geological Facts

The label in the image mentions 'Sphalerite', a major ore of zinc. Pegmatites are famous for producing the largest individual crystals ever found on Earth due to the unique fluid dynamics of their formation.

Field Identification & Locations

Identify in the field by the exceptionally large crystal grain size (pegmatitic texture) and the presence of elongated black tourmaline (schorl) needles in a white quartz/feldspar matrix.

Identified on: 4/13/2026

Mode: Standard