Kinoit

Kinoit
	Arizona , United States (image width 5 cm)
General and classification
chemical formula	Ca 2 Cu 2 Si 3 O 8 (OH) 4 ; Ca 2 Cu 2 (H 2 O) 2 [Si 3 O 10 ]; Ca 2 Cu 2 [Si 3 O 10 ] · 2 H 2 O;
Mineral class; (and possibly department)	Silicates and Germanates
System no. to Strunz ; and to Dana	9.BH.10 ; 57.01.02.01
Crystallographic Data
Crystal system	monoclinic
Crystal class ; symbol	monoclinic prismatic; 2 / m
Space group	P 2 1 / m (No. 11)
Lattice parameters	a = 6.99 Å ; b = 12.88 Å; c = 5.65 Å ; α = 90 °; β = 96.18 °; γ = 90 °
Formula units	Z = 2
Physical Properties
Mohs hardness	2.5
Density (g / cm 3 )	calculated: 3.193 ; measured: 3.13-3.19
Cleavage	very good (perfect according to {010}, clearly according to {001} and {100})
colour	azure blue, deep blue
Line color	bluish white
transparency	transparent to translucent
shine	Glass gloss
Crystal optics
Refractive indices	n α = 1.638 ; n β = 1.665 ; n γ = 1.676
Birefringence	δ = 0.038
Optical character	biaxial
Axis angle	2V = 64 ° (calculated), 68 ° (measured)
Pleochroism	strong
Other properties
Special features	Mg 2+ contamination possible

Kinoite is a seldom occurring mineral from the mineral class of " silicates and germanates " with the chemical composition Ca ₂ Cu ₂ Si ₃ O ₈ (OH) ₄ and therefore, chemically speaking, a calcium - copper - hydroxy - silicate.

Kinoite crystallizes in the monoclinic crystal system and is often found in the form of tabular azure-blue crystals up to a few millimeters in diameter or as crystal turf on surfaces of several square centimeters. The mineral usually occurs with apophyllite and sometimes associated with ruizit and gilalite . Kinoit is transparent to translucent and has a glass luster on the surface of the crystals .

Etymology and history

Kinoit was named in honor of the Italian Jesuit Eusebio Francisco Kino , who worked among other things as a missionary , astronomer and cartographer in the northwest of today's Mexico and in the southwest of today's USA. The type locality of the mineral is in the Santa Rita Mountains in Arizona , USA.

The type material of Kinoit is stored at the Department of Geology at the University of Arizona and registered by the National Museum of Natural History under catalog no. 122395 led.

classification

Since the 9th edition of Strunz's mineral systematics , the mineral has belonged to the department of “ Group silicates (sorosilicates)” and there, together with Aminoffit , Akatoreit and Fencooperit, to the subdivision “Group silicates with Si ₃ O ₁₀ or larger anions; Cations in tetrahedral [4] greater and greater coordination ”.

Crystal structure

Kinoite crystallizes in the monoclinic crystal system in the space group P 2 ₁ / m (space group no. 11) with the lattice parameters a = 6.990, b = 12.88 and c = 5.65 Å as well as two formula units per unit cell . Template: room group / 11

Education and Locations

The type material of Kinoit forms veins and single crystals, which are embedded in minerals of the apophyllite group and formed in tectonically stressed copper-bearing skarns . The mineral is next Hydroxyapophyllit- (K) and Fluorapophyllit- (K) in some cases also with Gilalit , Ruizit , calcite , Junitoit , Dioptas as well as silver and cuprite associated.

As a rare mineral formation, Kinoite is not very common. About 20 sites are known to date (as of 2020). In addition to its type locality, the Santa Rita Mountains in Arizona, five other sites are known in the same US state. Three of them are in the Helvetia-Rosemont Mining District, and another in the Twin Buttes Mine in the Pima Mining District, each in Pima County . Kinoite was also found in the Christmas Mine in the Banner Mining District in Gila County, also Arizona. The mineral was also found in the United States in the Bawana Mine in the Rocky Mining District in Beaver County , Utah and twelve other sites on Lake Superior , eleven of them in Michigan and one in Minnesota near Duluth .

Outside the USA, Kinoit has so far only been detected in the Fuka mine near Takahashi in Okayama Prefecture on the island of Honshū in Japan.

use

Due to its rarity and its comparatively low copper content, Kinoite is of no importance as a copper ore. Levels of the mineral are only sought after by collectors.

literature

John W. Anthony, Robert B. Laughon: Kinoite, a new hydrous copper calcium silicate mineral from Arizona . In: American Mineralogist . tape 55 , no. 5-6 , June 1, 1970, pp. 709-715 .
Robert B. Laughon: The Crystal Structure of Kinoite . In: American Mineralogist . tape 56 , no. 1-2 , February 1, 1971, pp. 193-200 .

Web links

Kinoit . In: Mineralienatlas , accessed on April 17, 2020.
Kinoite Mineral Data . In: Mineralogy Database - webmineral.com , accessed April 17, 2020.

Individual evidence

↑ Mineral formula according to Mineralienatlas.de , accessed on April 18, 2020.
↑ Mineral formula according to mindat.org , accessed April 18, 2020.
^ Mineral formula according to Rösler, Hans Jürgen : Textbook of Mineralogy . 3. Edition. VEB German publishing house for basic industry , Leipzig 1984, p. 501 .
↑ ^a ^b ^c ^d ^e ^f ^g Kinoite. In: mindat.org . Hudson Institute of Mineralogy, accessed April 17, 2020 .
^ Rösler, Hans Jürgen : Textbook of Mineralogy . 3. Edition. VEB German publishing house for basic industry , Leipzig 1984, p. 501 .

[1] Mineral formula according to Mineralienatlas.de , accessed on April 18, 2020.

[2] Mineral formula according to mindat.org , accessed April 18, 2020.

[Rösler_Formel-3] Mineral formula according to Rösler, Hans Jürgen : Textbook of Mineralogy . 3. Edition. VEB German publishing house for basic industry , Leipzig 1984, p. 501 .

[mindat-4] ↑ ^a ^b ^c ^d ^e ^f ^g Kinoite. In: mindat.org . Hudson Institute of Mineralogy, accessed April 17, 2020 .

[Rösler-5] Rösler, Hans Jürgen : Textbook of Mineralogy . 3. Edition. VEB German publishing house for basic industry , Leipzig 1984, p. 501 .