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Formula: (NH4,Mg0.5)5(Al5Si31O72).22H2O
Tectosilicate (framework silicate), ferrierite subgroup,
zeolite group,
Crystal System: Orthorhombic
Specific gravity: 2.154 calculated
Streak: White
Colour: White
Luminescence: Intense bluish white fluorescence under both short wave (254 nm) and long wave (366 nm) UV; such
fluorescence is unusual for zeolites (CM 57.1.81-90).
Environments
Ferrierite-NH4 is a relatively new mineral, approved in 2018.
Localities
At the type locality, the Libous quarry, Březno, Chomutov District, Ústí nad Labem Region, Czech Republic, specimens
containing ferrierite-NH4 were collected from a large, active open coal pit. The first analysed
samples and the holotype were collected from the base of the main coal seam and occur there as radiating aggregates of
elongated tabular crystals or fine fibrous aggregates with silky luster up to 1.5 mm across, consisting of very thin
flattened prismatic crystals in fractures in abundant pelosiderite nodules in
association with calcite, siderite,
whewellite, quartz,
opal, baryte and
clay minerals. Later, occurrences of ferrierite-NH4 were
also discovered in the hanging wall of the main coal seam. Above the coal seam there is a 1.5 m thick layer of dark
brown carbonaceous shale with abundant small
siderite concretions bearing radiating aggregates of
ferrierite-NH4
(CM 57.1.81-90).
At the Bílina coal mine, Bílina, Teplice District, Ústí nad Labem Region, Czech Republic, specimens containing
ferrierite-NH4 were collected from the southern part of the large, active open coal pit. It was
found only in the proximity of the Bílina fault, in fractures of carbonate concretions, as well as in
siderite and sandstone bands
in the base of the main coal seam. Associated minerals are marcasite,
pyrite, baryte,
sphalerite and
supergene gypsum
(CM 57.1.81-90).
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