Quartz, Clinochlore and Siderite

ID	215
Mineral	Quartz Clinochlore Siderite
Location	Iraí - Rio Grande Do Sul - Brazil
Fluorescence	LW-UV: close SW-UV: close
Mindat.org	View Quartz information at mindat.org View Clinochlore information at mindat.org View Siderite information at mindat.org

Mindat data

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

ID	1016
Long ID	1:1:1016:6
Entry type	5
Description	A group of mostly monoclinic (also triclinic or orthorhombic) micaceous phyllosilicate minerals with a structure consisting of T-O-T layers with two layers having their silicate tetrahedral apices pointing towards each other, separated by an interlayer...
Hardness (min)	2.0
Hardness (max)	2.5
Streak	Colorless
Crystal System	Monoclinic
shortcode_ima	Chl

ID	3647
Long ID	1:1:3647:0
Formula	`Fe(CO₃)`
IMA Status	0 1
Other Occurrences	Most often found in bedded sedimentary deposits with a biological component, with shales, clays and coal beds - suggesting that the siderite is biogenically created under low-oxygen and low-Ph conditions. It is also found in metamorphosed sedimentary rocks as more massively crystalline material, as a primary gangue mineral in hydrothermal deposits, and in pegmatites, including nepheline syenite pegmatites; as bog deposits.
Industrial	An ore of iron when found in sufficient volumes to be economically recoverable.
Diapheny	Translucent
Cleavage	Perfect on {10_11}.
Tenacity	brittle
Colour	Yellowish-brown to greyish-brown, pale yellow to tannish, grey, brown, green, red, black and, rarely, colourless; tarnished iridescent at times; colourless to yellow and yellow-brown in transmitted light.
Hardness (min)	3.5
Hardness (max)	4.5
Lustre	Vitreous
About the name	Named in 1845 by Wilhelm Karl von Haidinger from the Greek "σίδηρος" (sideros), "iron", in allusion to its composition.
Streak	White
Crystal System	Trigonal
Cleavage Type	Perfect
Fracture type	Irregular/Uneven,Conchoidal
Morphology	Crystals usually rhombohedral {10_11} or {011_2}, often curved or with composite faces; also more rarely thin to thick tabular {0001}, prismatic [0001] with {11_20}, or scalenohedral; most often found as massive material, either fine-grained in sedimentary settings or massively crystalline in metamorphic settings; may also be botryoidal or globular with a fibrous internal structure.
Twinning	On {01_12}, lamellar, uncommon, with translation gliding on {0001} or {10_11}. On {0001}, rare.
shortcode_ima	Sd
Group	Calcite Group

Price: € 15

Dimensions: Not registered

Weight: 163 g

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Notes:

Symbol	Element
C	Carbon
Fe	Iron
O	Oxygen
Si	Silicium

Quartz, Clinochlore and Siderite

Mindat data

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