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Formula: Ba2(Si12Al4)O32.12H2O
Tectosilicate (framework silicate), phillipsite subgroup,
zeolite group, forms a series with
phillipsite-Ca
Crystal System: Monoclinic
Specific gravity: 2.41 to 2.47 measured, 2.448 calculated
Hardness: 4 to 5
Streak: White
Colour: Colourless, white, grey, pink, yellow, brown
Common impurities: Na,Ca
Sedimentary environments (rarely)
Metamorphic environments
Basaltic cavities
Harmotome occurs in basaltic cavities associated with calcite and rarely
natrolite. It has also been reported in
tuff
associated with calcite, laumontite and
pyrite
(DHZ 4 p398).
At Nisikkatch lake, Saskatchewan, Canada, harmotome occurs in veins in
gneiss associated with microcline variety
hyalophane and
albite
(DHZ 4 p398).
In northern Italy harmotome occurs in graphite lenses in
gneiss with quartz,
sphalerite and galena
(DHZ 4 p398).
In the Ural mountains, Russia, harmotome occurs in bauxite with
kaolinite and halloysite
(DHZ 4 p398).
At Snailbeach mine, near Minsterley, Shropshire, England, UK, harmotome occurs with calcite
(RES p273).
At the Struy lead mines, Inverness, Scotland, UK, harmotome occurs in hydrothermal veins with
sphalerite, baryte and
calcite
(DHZ 4 p398).
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