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Cannel is a type of bituminous coal,[1] also categorised as terrestrial-type oil shale.[2][3][4] Owing to its physical morphology and low mineral content cannel is considered to be coal, but by its texture and composition of the organic matter it is also considered to be oil shale.[5] Although historically the term cannel coal has been used interchangeably with boghead coal, a more recent classification system restricts cannel coal to terrestrial origin, and boghead coal to lacustrine environments, sedimentary deposits formed at the bottom of ancient lakes.[2]
Cannel coal commanded a premium price as a fuel for use in home fireplaces. It burned longer than wood, and had a clean, bright flame.[6] It has also been used as jewellery since the Neolithic period, with pieces appearing in Scotland (often alongside jet) dating from the centuries before 3500 BCE.[7]
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