Harmotome is a mineral, one of the rarer zeolites; a hydrated barium silicate with formula: .
Name and discovery
Named from the Greek words (a joint) and (to cut) by René Just Haüy in 1801
because the pyramid divides parallel to the plane that passes through the terminal edges.
It was first described in 1801 from an occurrence in the
Harz Mountains, Lower
Saxony,
Germany.
Location
Like other zeolites, harmotome occurs with calcite in the amygdaloidal cavities of volcanic rocks, for example, in the dolerites of
Dumbartonshire, and as fine crystals in the agate-lined cavities in the melaphyre of
Oberstein in Germany. It also occurs in gneiss, and sometimes in metalliferous veins. At Sankt Andreasberg in the
Harz it is found in the lead and silver veins; and at
Strontian in
Argyll in lead veins, associated with
brewsterite (a strontium and barium zeolite), barytes and calcite.
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