Selenite, Aragonite and Siderite

ID	586
Mineral	Selenite Aragonite Siderite
Location	Cavnic Mine - Cavnic - Maramures - Romania
Fluorescence	LW-UV: close SW-UV: close
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Mindat data

ID	5527
Long ID	1:1:5527:3
IMA Status	0 1
Variety of	1784
Entry type	2
Description	The name 'selenite' is mostly synonymous with gypsum but has been used historically to describe the transparent variety, as opposed to satin spar gypsum for the fibrous variety and alabaster for the fine-grained massive form. The original name was ...
Diapheny	Transparent
Colour	Colourless, light tints due to included matter
Hardness (min)	2.0
Hardness (max)	2.0
About the name	From the Greek σεληνη, for "moon", in allusion to the moon-like white reflections of the mineral or to the quality of the light transmitted by translucent gypsum slabs of cleavages used as windows.
Crystal System	Monoclinic
Fracture type	Micaceous

ID	307
Long ID	1:1:307:6
Formula	`Ca(CO₃)`
IMA Status	0 1
Other Occurrences	As speleothems in limestone caves; as pisolites, sinters and massive lamellar deposits at geysers and hot springs; as seafloor oolites; with siderite in iron deposits; with calcite and dolomite and other magnesium minerals in altered serpentinites, dunites and peridotites; and as a replacement mineral in various rock types and ore deposits, formed from low-temperature and pressure aqueous solutions.
Discovery Year	1797
Diapheny	Transparent,Translucent
Cleavage	On {010} distinct; On {110} and {011} very indistinct.
Tenacity	brittle
Colour	Colorless to white or grey, often stained various hues by impurities, such as blue, green, red or violet; colourless in transmitted light.
Hardness (min)	3.5
Hardness (max)	4.0
Luminescence	Fluoresces pale rose, yellow, bluish, often with greenish phosphorescence, under LW, yellowish in SW.
Lustre	Vitreous to resinous.
About the name	Named in 1797 by Abrahan Gottlob Werner for the type locality, the village of Molina de Aragón, Spain, and not the province of Aragón, a mistake made by several later writers.
Streak	Uncolored/white.
Crystal System	Orthorhombic
Cleavage Type	Distinct/Good
Fracture type	Sub-Conchoidal
Morphology	Short to long prismatic [100], sometimes flattened {010}; acicular, often with steep pyramidal or domed terminations; or tabular {001}; also stalactic, columnar, in stellate or radiating aggregates, and fibrous crusts of tiny acicular crystals.
Twinning	Single crystals are typically twinned cyclically on {110} producing pseudo-hexagonal aggregates of contact and penetration twins. Polysynthetic twinning produces lamellae or fine striations parallel to [100].
UV	Pale rose, yellow, white or bluish, with greenish or white phosphorescence (LW UV); yellowish (SW UV).
Thermal Behaviour	Begins to convert to calcite at about 400°C when heated in dry air. Thermoluminescent.
shortcode_ima	Arg
Group	Aragonite Group

ID	3647
Long ID	1:1:3647:0
Formula	`Fe(CO₃)`
IMA Status	0 1
Other Occurrences	Most often found in bedded sedimentary deposits with a biological component, with shales, clays and coal beds - suggesting that the siderite is biogenically created under low-oxygen and low-Ph conditions. It is also found in metamorphosed sedimentary rocks as more massively crystalline material, as a primary gangue mineral in hydrothermal deposits, and in pegmatites, including nepheline syenite pegmatites; as bog deposits.
Industrial	An ore of iron when found in sufficient volumes to be economically recoverable.
Diapheny	Translucent
Cleavage	Perfect on {10_11}.
Tenacity	brittle
Colour	Yellowish-brown to greyish-brown, pale yellow to tannish, grey, brown, green, red, black and, rarely, colourless; tarnished iridescent at times; colourless to yellow and yellow-brown in transmitted light.
Hardness (min)	3.5
Hardness (max)	4.5
Lustre	Vitreous
About the name	Named in 1845 by Wilhelm Karl von Haidinger from the Greek "σίδηρος" (sideros), "iron", in allusion to its composition.
Streak	White
Crystal System	Trigonal
Cleavage Type	Perfect
Fracture type	Irregular/Uneven,Conchoidal
Morphology	Crystals usually rhombohedral {10_11} or {011_2}, often curved or with composite faces; also more rarely thin to thick tabular {0001}, prismatic [0001] with {11_20}, or scalenohedral; most often found as massive material, either fine-grained in sedimentary settings or massively crystalline in metamorphic settings; may also be botryoidal or globular with a fibrous internal structure.
Twinning	On {01_12}, lamellar, uncommon, with translation gliding on {0001} or {10_11}. On {0001}, rare.
shortcode_ima	Sd
Group	Calcite Group

MinID: 1KP-37H

Price: € 150

Dimensions: Not registered

Weight: Not registered

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Notes:

Symbol	Element
C	Carbon
Ca	Calcium
Fe	Iron
H	Hydrogen
O	Oxygen
S	Sulfur

Selenite, Aragonite and Siderite

Mindat data

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