mineral

Micrometeorite (Spherule)

Extraterrestrial Accretion Spherule

Hardness: 5-6 (Mohs); Color: Metallic black, brown, or translucent olive; Luster: Sub-metallic to vitreous; Structure: Spherical; Specific Gravity: 3.0-4.0.

Hardness: 5-6 (Mohs)
Color: Metallic black, brown, or translucent olive
Luster: Sub-metallic to vitreous

Identified May 30, 2026More mineral →

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Physical properties

Hardness: 5-6 (Mohs); Color: Metallic black, brown, or translucent olive; Luster: Sub-metallic to vitreous; Structure: Spherical; Specific Gravity: 3.0-4.0.

Formation & geological history

Formed when micrometeoroids enter Earth's atmosphere at high speeds (up to 72 km/s). Frictional heating causes the particle to melt and solidify into a sphere before hitting the surface.

Uses & applications

Scientific study to understand the chemical composition of the solar system and accretion history; highly valued by micrometeorite collectors.

Geological facts

Thousands of tons of this material fall to Earth every year. They are some of the oldest materials in our solar nebula. High-resolution microscopy and magnets are often used to find them.

Field identification & locations

Identify by spherical shape and magnetic response. Often found in accumulation zones like rooftops, deep-sea sediments, or Antarctic ice. Small size (sub-millimeter) requires magnification.

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