Shatter Cone

Hardness: typically 6-7 (depends on host rock like limestone or sandstone); Color: light gray to brownish grey; Luster: dull to earthy; Texture: distinctive conical shape with radiating fractures (striations) spreading from an apex.

Formed by high-pressure shock waves produced by meteorite impacts or underground nuclear explosions. The rock is essentially shock-metamorphosed, where the pressure and heat briefly exceed the strength of the rock, creating these unique conical patterns. Ages range from millions to over a billion years depending on the impact site.

Primarily of geological and scientific interest; used by researchers to identify and document ancient meteorite impact craters. They are also popular with mineral and meteorite collectors.

Shatter cones are the only macroscopically visible evidence of impact shock that can be found in the field. They were once thought to be volcanic in origin until the high pressures required for their formation (2 to 30 GPa) were calculated.

Identify in the field by looking for 'horsetail' patterns of ridges and grooves that radiate from a single point. Commonly found at known impact structures like Sudbury (Canada), Vredefort (South Africa), or Kentland (Indiana, USA). Tip: The apex of the cone usually points toward the impact center.