Lazurite and Pyrite

ID	111
Mineral	Lazurite Pyrite
Location	Slyudyanka - Tounkinskaya valley - Russia
Fluorescence	LW-UV: close SW-UV: close
Mindat.org	View Lazurite information at mindat.org View Pyrite information at mindat.org

ID	2357
Long ID	1:1:2357:9
Formula	`Na₇Ca(Al₆Si₆O₂₄)(SO₄)(S₃)^1- · H₂O`
IMA Status	0
General Appearance	Velvet Lazurite of Sapozhnikov et al (2021)
Occurrence	The Malo-Bystrinskoe lazurite gem deposit, Baikal Lake area, Eastern Siberian region, Russia.
Other Occurrences	Contact metamorphic mineral in marble and skarns. Also in some syenites and alkaline volcanics.
Industrial	The blue mineral in Lapis Lazuli, an ornamental stone
Discovery Year	1890
Diapheny	Opaque
Cleavage	Imperfect on {110}
Tenacity	brittle
Colour	Ultramarine, midnight blue, bluish green, green
Hardness (min)	5.0
Hardness (max)	5.5
About the name	From the Persian "Lazhward" for "blue." Also for its dark blue color resemblance to "azurite." Both Lazurite and azurite derive from "Lazhward". Dana (System of Mineralogy, 1868) considered lapis-lazuli to be the dark blue mineral in the lazulite-calcite rock of the same name, but these were renamed lazurite in 1891 [[1\| Brögger W C, Bäckström H 1891]].
Streak	Bright blue for lazurite, white for the small cell hauynes.
Crystal System	Isometric
Cleavage Type	Imperfect/Fair
Fracture type	Sub-Conchoidal
Morphology	Dodecahedrons, cubes, granular, disseminated, massive.
Twinning	None observed
UV	The opaque ultramarine and midnight blue Lazurites are not fluorescent. The translucent green and blue hauynes have an orange brown fluorescence under Long Wave UV.
shortcode_ima	Lzr
Group	Sodalite Group

ID	3314
Long ID	1:1:3314:1
Formula	`FeS₂`
IMA Status	0 1
Other Occurrences	Common in many rock types, igneous, metamorphic and sedimentary.
Diapheny	Opaque
Cleavage	Indistinct on {001}.
Tenacity	brittle
Colour	Pale brass-yellow
Hardness (min)	6.0
Hardness (max)	6.5
About the name	Named in antiquity from the Greek "pyr" for "fire", because sparks flew from it when struck with another mineral or metal. Known to Dioscorides (~50 CE) under the name "περι υληζ ιατρικηζ" which included both pyrite and chalcopyrite.
Streak	Greenish-black
Crystal System	Isometric
Cleavage Type	Poor/Indistinct
Fracture type	Irregular/Uneven,Conchoidal
Morphology	Typically cubic or pyritohedral (pentagonal dodecahedral), sometimes octahedral and combinations are common, resulting in striated faces. Less frequently octahedral, most commonly massive, granular, and sometimes radiating, reniform, discoidal or globular.
Twinning	On [110], interpenetrating ('Iron Cross Law'). Twin axis [001] and twin plane {011}, penetration and contact twins. Twinning on (111) was described by Nicol (1904), Goldschmidt and Nicol (1904) and Gaubert (1928), all of whom considered it rare.
UV	Not fluorescent in UV
Thermal Behaviour	Heated in a closed tube gives a sublimate of sulfur and a magnetic residue.
shortcode_ima	Py
Group	Pyrite Group

Price: € 5

Dimensions: Not registered

Weight: Not registered

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