igneous
Lava Rock with Fabric Impression
Scoria or Basalt with anthropogenic impressions
Hardness: 5-6 (Mohs); Color: Dark brown to black; Luster: Dull to sub-vitreous; Structure: Vesicular/aphanitic; Features: Cross-hatch woven impressions remaining on the surface.
- Hardness
- 5-6 (Mohs)
- Color
- Dark brown to black
- Luster
- Dull to sub-vitreous
Identified More igneous →
Explore Lava Rock with Fabric Impression in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 5-6 (Mohs); Color: Dark brown to black; Luster: Dull to sub-vitreous; Structure: Vesicular/aphanitic; Features: Cross-hatch woven impressions remaining on the surface.
Formation & geological history
Formed from the rapid cooling of mafic lava (basaltic) containing dissolved gases. This specific specimen indicates contact with a woven material, likely a man-made fabric or mat, while the lava was still plastic/molten.
Uses & applications
Primarily of archaeological or novelty interest. Scoria is usually used in landscaping, gas grills, and high-temperature insulation.
Geological facts
This specimen is unusual because it preserves the texture of a woven fabric ('lava casting'). It suggests the lava flowed over a man-made object or that a person pressed a material into the cooling rock.
Field identification & locations
Identify by looking for the bubbly (vesicular) texture of volcanic scoria combined with unnatural geometric patterns. Common in volcanic regions like Hawaii, Iceland, or Italy.
