Cassiterite and Quartz

ID	432
Mineral	Cassiterite Quartz
Location	Viloco Mine - Viloco - La Paz - Bolivia
Fluorescence	LW-UV: close SW-UV: close
Mindat.org	View Cassiterite information at mindat.org View Quartz information at mindat.org

Mindat data

ID	917
Long ID	1:1:917:7
Formula	`SnO₂`
IMA Status	0 1
Other Occurrences	In medium- to high-temperature hydrothermal veins and greisens, alluvial placers.
Discovery Year	1832
Diapheny	Transparent,Translucent,Opaque
Cleavage	{100} imperfect, {110} indistinct.
Tenacity	brittle
Colour	Black, yellow, brown, red or white.
Hardness (min)	6.0
Hardness (max)	7.0
Lustre	Adamantine, Metallic
About the name	The mineral name is derived from the term “Cassiterides” which was applied to 'islands off the western coast of Europe' in pre-Roman times. The exact location of these 'islands' has been hotly debated over the years. Current thought is that the source was probably mainland Spain and that even 2000 years ago, traders had a habit of providing misleading locality information to protect their sources.
Streak	Brownish white, white, greyish
Crystal System	Tetragonal
Cleavage Type	Imperfect/Fair
Fracture type	Irregular/Uneven,Sub-Conchoidal
Morphology	Untwinned crystals usually short prismatic [001] with {110} and {100} prominent. Long prismatic at times, or with acute terminations. Less commonly pyramidal. Faces {001} and {110} frequently uneven; faces in zone [10_1] and in zone [001] often striated parallel to their intersections. Fibrous, botryoidal crusts or concretionary masses. Granular, coarse to fine.
Twinning	1. On {011}, very common. Both contact and penetration twins; often repeated producing complex forms. Stellate fivelings at times. 2. Reported on {031}.
UV	Cassiterite will rarely show fluorescence, and only under SW UV, showing a yellow glow. See the caption and the child photos of: https://www.mindat.org/photo-693927.html https://www.mindat.org/photo-583447.html https://www.mindat.org/photo-915970.html See also: https://www.fluomin.org/uk/fiche.php?id=277
key_elements	0
shortcode_ima	Cst
Group	Rutile 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: € 10

Dimensions: Not registered

Weight: 31 g

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Notes:

Symbol	Element
O	Oxygen
Si	Silicium
Sn	Tin

Cassiterite and Quartz

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