Phlogopite and Pyrite

ID	20
Mineral	Phlogopite Pyrite
Location	Phalaborwa - Limpopo Provincie - South Africa
Fluorescence	LW-UV: close SW-UV: close
Mindat.org	View Phlogopite information at mindat.org View Pyrite information at mindat.org

ID	3193
Long ID	1:1:3193:2
Formula	`KMg₃(AlSi₃O₁₀)(OH)₂`
IMA Status	0 1
Other Occurrences	Contact and regional metamorphic limestones and dolomites, ultramafic rocks.
Discovery Year	1841
Diapheny	Transparent,Translucent
Cleavage	on {0001}
Tenacity	flexible
Colour	Brown, gray, green, yellow, or reddish brown
Hardness (min)	2.0
Hardness (max)	3.0
Luminescence	None
Lustre	Vitreous - Pearly
About the name	Named in 1841 by Johann Friedrich August Breithaupt from the Greek φλογωποζ "phlogopos" for "resembling fire", in allusion to the red tint of the original specimens.
Streak	White
Crystal System	Monoclinic
Cleavage Type	Perfect
Fracture type	Micaceous
Morphology	Six sided crystals, thick tabular to prismatic, commonly tapered.
Twinning	Composition plane {001}, twin axis [310]
Comment Luster	sub-metallic on cleavage
shortcode_ima	Phl
Group	Biotite

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: € 15

Dimensions: Not registered

Weight: 157 g

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