mineral

Fulgurite

Lechatelierite (Fused Silica)

Hardness of 6-7 on the Mohs scale, grayish-white or tan color, vitreous to dull luster, amorphous crystal structure (glassy, non-crystalline), brittle tenacity, specific gravity around 2.2.

Identified August 7, 2026More mineral →

Explore Fulgurite in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness of 6-7 on the Mohs scale, grayish-white or tan color, vitreous to dull luster, amorphous crystal structure (glassy, non-crystalline), brittle tenacity, specific gravity around 2.2.

Formation & geological history

Formed when a high-voltage lightning strike hits sand or soil, causing instantaneous melting and vitrification of silica-rich materials. Typically forms tubular or branching root-like structures.

Uses & applications

Prized by mineral collectors, used in scientific research regarding ancient atmospheric conditions and lightning strikes, and sometimes used in metaphysical jewelry.

Geological facts

Often referred to as 'fossilized lightning', fulgurites can sometimes reach several meters deep into the earth depending on the intensity of the lightning strike and the composition of the soil.

Field identification & locations

Found in sandy deserts, beaches, and high-altitude mountain peaks where lightning is frequent. Identify by its hollow, glass-lined interior tubes and fused sandy exterior texture.