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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).
Localities
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).
Harmotome from Northern Italy - Image
In the Ural mountains, Russia, harmotome occurs in bauxite with
kaolinite and halloysite
(DHZ 4 p398).
At Malmberget, Gällivare, Norrbotten County, Sweden, harmotome is fairly common as crystals
from 3 to 10 mm long covering walls of thin fissures. Drusy harmotome covers
feldspar crystals in specimens from the Hermelin mine
(MinRec 56.5.592).
Harmotome from Malmberget -
Image
At Snailbeach mine, near Minsterley, Shropshire, England, UK, harmotome occurs with calcite
(RES p273).
At Allt Tighe Cumhaig, Struy, Strathglass, Aird and Loch Ness, Highland, Scotland, UK, harmotome occurs in
hydrothermal veins with
sphalerite, baryte and
calcite
(DHZ 4 p398).
Harmotome from Allt Tighe Cumhaig -
Image
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