Hematite and Quartz

ID	306
Mineral	Hematite Quartz
Location	Midelt - Draa-Tafilalet - Morocco
Fluorescence	LW-UV: close SW-UV: close
Mindat.org	View Hematite information at mindat.org View Quartz information at mindat.org

Mindat data

ID	1856
Long ID	1:1:1856:8
Formula	`Fe₂O₃`
IMA Status	0 1
Other Occurrences	Large ore bodies of hematite are usually of sedimentary origin; also found in high-grade ore bodies in metamorphic rocks due to contact metasomatism, and occasionally as a sublimate on igneous extrusive rocks ("lavas") as a result of volcanic activity. It is also usually the cause of red soils all over the planet.
Industrial	A major ore of iron.
Diapheny	Opaque
Tenacity	brittle
Colour	Steel-grey to black in crystals and massively crystalline ores, dull to bright "rust-red" in earthy, compact, fine-grained material.
Hardness (min)	5.0
Hardness (max)	6.0
Luminescence	None
Lustre	Metallic
About the name	Originally named about 300-325 BCE by Theophrastus from the Greek, "αιματίτις λίθος" ("aematitis lithos") for "blood stone". It is possibly the first mineral ever named ending with a "-ite" suffix. Translated in 79 by Pliny the Elder to haematites, "bloodlike", in allusion to the vivid red colour of the powder. The modern form evolved by authors frequently simplifying the spelling by excluding the "a", somewhat in parallel with other words originally utilising the root "haeme".
Streak	Reddish brown ("rust-red")
Crystal System	Trigonal
Cleavage Type	None Observed
Fracture type	Irregular/Uneven,Sub-Conchoidal
Morphology	Crystals generally thick to thin tabular {0001}, rarely prismatic [0001] or scalenohedral; also rarely rhombohedral {10_11}, producing pseudo-cubic crystals. Often found in sub-parallel growths on {0001} or as rosettes ("iron roses.") Sometimes in micaceous to platy masses. May be compact columnar or fibrous masses, sometimes radiating, or in reniform masses with a smooth fracture ("kidney ore"), and botryoidal and stalactic. Frequently in earthy masses, also granular, friable to compact, concretionary and oolitic.
Twinning	Penetration twins on {0001}, or with {10_10} as a composition plane. Frequently exhibits a lamellar twinning on {10_11} in polished section.
UV	None.
shortcode_ima	Hem
Group	Hematite 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: € 30

Dimensions: Not registered

Weight: 1962 g

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Notes:

Symbol	Element
Fe	Iron
O	Oxygen
Si	Silicium

Hematite and Quartz

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