Pyrite and Quartz

ID	574
Mineral	Pyrite Quartz
Location	Unknown - Unknown - Unknown - Unknown
Fluorescence	LW-UV: close SW-UV: close
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Mindat data

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

ID	3337
Long ID	1:1:3337:0
Formula	`SiO₂`
IMA Status	0 1
Other Occurrences	Most of them...
Industrial	Ore for silicon, glassmaking, frequency standards, optical instruments, silica source for concrete setting, filtering agents as sand. A major component of sand.
Diapheny	Transparent,Translucent
Cleavage	The rhombohedral cleavage r{10_11} is most often seen, there are at least six others reported.
Tenacity	brittle
Colour	Colorless, purple, rose, red, black, yellow, brown, green, blue, orange, etc.
Hardness (min)	7.0
Hardness (max)	7.0
Luminescence	Triboluminescent
Lustre	Vitreous
About the name	Quartz has been known and appreciated since pre-historic times. The most ancient name known is recorded by Theophrastus in about 300-325 BCE, κρύσταλλος or kristallos. The varietal names, rock crystal and bergcrystal, preserve the ancient usage. The root words κρύοσ signifying ice cold and στέλλειυ to contract (or solidify) suggest the ancient belief that kristallos was permanently solidified ice. The earliest printed use of "querz" was anonymously published in 1505, but attributed to a physician in Freiberg, Germany, Ulrich Rülein von Kalbe (a.k.a. Rülein von Calw, 1527). Agricola used the spelling "quarzum" (Agricola 1530) as well as "querze", but Agricola also referred to "crystallum", "silicum", "silex", and silice". Tomkeieff (1941) suggested an etymology for quartz: "The Saxon miners called large veins - Gänge, and the small cross veins or stringers - Querklüfte. The name ore (Erz, Ertz) was applied to the metallic minerals, the gangue or to the vein material as a whole. In the Erzgebirge, silver ore is frequently found in small cross veins composed of silica. It may be that this ore was called by the Saxon miners 'Querkluftertz' or the cross-vein-ore. Such a clumsy word as 'Querkluftertz' could easily be condensed to 'Querertz' and then to 'Quertz', and eventually become 'Quarz' in German, 'quarzum' in Latin and 'quartz' in English." Tomkeieff (1941, q.v.) noted that "quarz", in its various spellings, was not used by other noted contemporary authors. "Quarz" was used in later literature referring to the Saxony mining district, but seldom elsewhere. Gradually, there were more references to quartz: E. Brown in 1685 and Johan Gottschalk Wallerius in 1747. In 1669, Nicolaus Steno (Niels Steensen) obliquely formulated the concept of the constancy of interfacial angles in the caption of an illustration of quartz crystals. He referred to them as "cristallus" and "crystallus montium". Tomkeieff (1941) also noted that Erasmus Bartholinus (1669) used the various spellings for "crystal" to signify other species than quartz and that crystal could refer to other "angulata corpora" (bodies with angles): "In any case in the second half of the XVIIIth century quartz became established as a name of a particular mineral and the name crystal became a generic term synonymous with the old term 'corpus angulatum'."
Streak	White
Crystal System	Trigonal
Cleavage Type	Poor/Indistinct
Fracture type	Conchoidal
Twinning	Dauphiné law. Brazil law. Japan law. Others for beta-quartz...
Thermal Behaviour	Transforms to beta-quartz at 573° C and 1 bar (100 kPa) pressure.
shortcode_ima	Qz

Price: € 3

Dimensions: Not registered

Weight: Not registered

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Notes:

Symbol	Element
Fe	Iron
O	Oxygen
S	Sulfur
Si	Silicium

Pyrite and Quartz

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