Azurite, Malachite and Goethite

ID	391
Mineral	Azurite Malachite Goethite
Location	New South Wales - Australia
Fluorescence	LW-UV: close SW-UV: close
Mindat.org	View Azurite information at mindat.org View Malachite information at mindat.org View Goethite information at mindat.org

ID	447
Long ID	1:1:447:3
Formula	`Cu₃(CO₃)₂(OH)₂`
IMA Status	0 1
Other Occurrences	Found largely in the oxidized portions of copper deposits, it is a secondary mineral formed by the action of carbonated water acting on copper-containing minerals, or from Cu-containing solutions, such as CuSO^4 or CuCl^2 reacting with limestones.
Industrial	A very minor ore of copper.
Discovery Year	1824
Diapheny	Transparent,Translucent
Cleavage	Perfect on {011}; on {100} fair; on {110} in traces.
Tenacity	brittle
Colour	Azure blue, blue, light blue, or dark blue; light blue in transmitted light
Hardness (min)	3.5
Hardness (max)	4.0
Luminescence	None
Lustre	Vitreous
About the name	From the ancient Persian lazhward, meaning "blue", in allusion to the color. Name changed to azurite in 1824 by François Sulpice Beudant.
Streak	Light blue
Crystal System	Monoclinic
Cleavage Type	Perfect
Fracture type	Conchoidal
Morphology	Tabular {001}, less common {102} or {_102}; prismatic [001] or [010]; sometimes equant or even rhombohedral; faces may be wavy with striations on {001} parallel to "a", on {100} parallel to "b." May also be massive, stalactic, or botryoidal.
Twinning	Rare, across {_101}, {_102} or {001}.
UV	None.
key_elements	0
shortcode_ima	Azu

ID	2550
Long ID	1:1:2550:4
Formula	`Cu₂(CO₃)(OH)₂`
IMA Status	0 1
Other Occurrences	It is the most common secondary mineral found in the oxidized zones of copper deposits.
Industrial	A minor ore of copper when abundant enough in a copper deposit.
Discovery Year	Unno
Diapheny	Opaque
Cleavage	Perfect on {_201}, fair on {010}.
Tenacity	brittle
Colour	Bright green, with crystals deeper shades of green, even very dark to nearly black; green to yellowish green in transmitted light.
Hardness (min)	3.5
Hardness (max)	4.0
About the name	Named in antiquity (see Pliny the Elder, 79 CE) molochitus after the Greek μαλαχή, "mallows," in allusion to the green color of the leaves. Known in the new spelling, malachites, at least by 1661.
Streak	Light green
Crystal System	Monoclinic
Cleavage Type	Perfect
Fracture type	Splintery
Morphology	Crystals uncommon, usually short or long prismatic or acicular, parallel to [001]; often grouped in rosettes, sprays, or tufts. Botryoidal to mammillary aggregates of radiating fibrous crystals more common. It may also be massive, compact, and stalactitic.
Twinning	Untwinned crystals are extremely rare. Typically twinned on {100}, sometimes as penetration or polysynthetic twinning with the axis parallel to [201].
Thermal Behaviour	Loses water at about 315°, leaving tenorite.
key_elements	0
shortcode_ima	Mlc
Group	Rosasite Group

ID	1719
Long ID	1:1:1719:6
Formula	`FeO(OH)`
IMA Status	0 1
Other Occurrences	Common weathering product, primary hydrothermal mineral, bog and marine environments.
Industrial	Iron ore
Discovery Year	1806
Diapheny	Opaque
Cleavage	{010}; {100} less perfect.
Tenacity	brittle
Colour	Brownish black, yellow-brown, reddish brown
Hardness (min)	5.0
Hardness (max)	5.5
About the name	Named in 1806 by Johann Georg Lenz in honor of the German poet, novelist, playwrighter, philosopher, politician, and geoscientist Johann Wolfgang von Goethe [August 28, 1749, Frankfurt, Germany – March 22, 1832, Weimar, Germany]. Goethe was Chief Minister of State of Weimar. (Portions of the Goethe mineral collection are reputedly held by the Goethe Society in New York, New York, USA.)
Streak	Yellowish brown, orange-yellow, ocher-yellow
Crystal System	Orthorhombic
Cleavage Type	Perfect
Fracture type	Irregular/Uneven
Morphology	Prismatic [001] and striated [001]; also flattened into tablets or scales on {010}. Velvety aggregates of capillary crystals to acicular [001] and long prismatic forms often radially grouped. Massive, reniform, botryoidal, stalactitic. Bladed or columnar. Compact or fibrous concretionary nodules. Oolitic.
Twinning	Apparently none reported, but see https://www.mindat.org/mesg-631125.html and compare twinning in isostructural diaspore.
Thermal Behaviour	Heated in a closed tube, gives off water.
shortcode_ima	Gth
Group	Diaspore Group

Price: € 2

Dimensions: Not registered

Weight: Not registered

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