sedimentary

Amber-bearing Coal/Sedimentary Rock

Bituminous coal or carbonaceous siltstone with Fossilized Tree Resin (C10H16O)

Hardness: 2-2.5 (amber inclusion), 0.5-2.5 (host rock); Color: Dark brown to black matrix with honey-yellow/brown inclusion; Luster: Dull (rock) to resinous (inclusion); Structure: Amorphous; Cleavage: None/Conchoidal.

Hardness: 2-2
Color: Dark brown to black matrix with honey-yellow/brown inclusion
Luster: Dull (rock) to resinous (inclusion)

Identified March 27, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed from compressed plant matter in swampy environments during the Carboniferous to Cretaceous periods. The inclusion is fossilized resin (amber) exuded by ancient trees and buried in anaerobic sediments.

Uses & applications

Primarily used as a fossil specimen for educational or hobbyist collecting. High-grade amber is used in jewelry; the host rock (if coal) is used for fuel, though specimens like this are mostly decorative.

Geological facts

Amber in coal is relatively common in regions like the Baltic or parts of the UK and US. It preserves a chemical record of ancient forests and can occasionally trap prehistoric insects or plant debris.

Field identification & locations

Identify in the field by looking for translucent, glassy nodules embedded in dark, soft, or crumbly sedimentary rock. Collectors should look for signs of 'resin' that glows under UV light or feels warm to the touch.

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