Hoganite
| Hoganite | |
|---|---|
 |
|
| General and classification | |
| other names |
IMA 2001-029 |
| chemical formula | Cu (CH 3 COO) 2 · H 2 O |
|
Mineral class (and possibly department) |
Organic compounds |
|
System no. to Strunz and to Dana |
10.AA.35 ( 8th edition : IX / A.02) 02.50.07.01 |
| Similar minerals | Paceit |
| Crystallographic Data | |
| Crystal system | monoclinic |
| Crystal class ; symbol | monoclinic prismatic; 2 / m |
| Space group | C 2 / c (No. 15) |
| Lattice parameters |
a = 13.162 (3) Å ; b = 8.555 (2) Å; c = 13.850 (3) Å β = 117.08 (3) ° |
| Formula units | Z = 8 |
| Physical Properties | |
| Mohs hardness | 1.5 |
| Density (g / cm 3 ) | calculated: 1.910 |
| Cleavage | completely after {100}, clearly after {101} |
| Break ; Tenacity | clamshell; brittle |
| colour | bluish green to dark blue green |
| Line color | Light Blue |
| transparency | transparent |
| shine | Glass gloss |
| Crystal optics | |
| Refractive indices |
n α = 1.533 (2) n β = 1.541 (3) n γ = 1.554 (2) |
| Birefringence | δ = 0.0210 |
| Optical character | biaxial positive |
| Axis angle | 2V = 85 (5) ° (measured); 76.8 ° (calculated) |
| Other properties | |
| Chemical behavior | soluble in water |
Hoganite is an extremely rare, secondary mineral from the mineral class of " organic compounds " with the chemical composition Cu (CH 3 COO) 2 · H 2 O and therefore, chemically speaking, a copper acetate .
Hoganite crystallizes in the monoclinic crystal system and develops bluish-green, prismatic or tabular crystals up to about 0.6 mm. It is a comparatively soft mineral with a Mohs hardness of 1.5 and a pale blue color .
Etymology and history
The mineral was named after the Australian mineral collector Graham P. Hogan (* 1957) who was the first to find it in the Perilya Potosi Mine ( Broken Hill , New South Wales, Australia). It was analyzed and described in 2002 by DE Hibbs, Uwe Kolitsch, P. Leverett, JL Sharpe and PA Williams. In the same year it was officially recognized as a mineral by the IMA.
Acetates, as naturally occurring minerals, are extremely rare, although acetic acid is widely used in nature. Until hoganite was recognized as a mineral, calclacite was the only known representative of this class of substances, although it is of anthropogenic origin. Up until then it was assumed that calclacite would remain the only representative of the acetates and a purely natural formation of other acetates was considered very unlikely. With the recognition of hoganite as a mineral by the IMA, it is the first representative of this class of substances that was created without anthropogenic influence.
Type material of the mineral is stored in the Broken Hill Geocentre in Broken Hill, the Australian Museum in Sydney and the Museum of Victoria in Melbourne .
classification
In the 8th edition of the mineral systematics according to Strunz , which is out of date but still in use , Hoganite belonged to the department of "Salts of Organic Acids", where together with abelsonite , calclacite , dashkovaite , earlandite , formicaite , julienite , kafehydrocyanite , mellite , paceite it was a combined group "Other organic salts, including mellates , citrates and acetates " with the system no. IX / A.02 formed.
The 9th edition of Strunz's mineral systematics, which has been in effect since 2001 and is used by the International Mineralogical Association (IMA), also classifies Hoganit in the “Salts of organic acids” section. However, this is now clearly subdivided according to the substance groups that form the basis of the respective mineral, so that hoganite can be found in the sub-section "Acetate" according to its composition, where it is the only member of the unnamed group 10.AA.35 .
The systematics of minerals according to Dana also assigns the hoganite to the class and department of the same name of "organic minerals". Here he is the namesake of the " Hoganit group " with the system no. 50.02.07 and the other member Paceit within the sub-section "Salts of organic acids (mellitates, citrates, cyanates and acetates)".
Crystal structure
Hoganite crystallizes monoclinically in the space group C 2 / c (space group no.15 ) with the lattice parameters a = 13.162 (3) Å , b = 8.555 (2) Å, c = 13.850 (3) Å and β = 117.08 ( 3) ° as well as 8 formula units per unit cell .
Hoganite forms small prismatic or tabular crystals, whereby the prismatic formations are similar in shape to the crystals of tourmaline .
properties
Thermonalytical investigations have shown that hoganite behaves completely analogously to pure copper acetate . Like this, it gives off its water of crystallization at temperatures between 83 ° C and 95 ° C and decomposes above 222 ° C with the formation of copper (II) oxide , carbon dioxide and water.
Education and Locations
For Hoganit only the type locality Perilya Potosi Mine (Potosi Mine) in Broken Hill has become known. Here, hoganite was formed alongside paceite in the so-called iron hat of the deposit through the reaction of weathered ores with decomposing plant material, especially with rotting leaves. Furthermore, the formation of decaying wooden structures in the corresponding mining facilities is discussed. It is important to the first users that the plant decomposition products were not caused by humans. The mineral is demonstrably formed at the place where it was found and not afterwards as with calclacite ; it is therefore not a museum artifact.
The mineral occurs at this location as an isolated, prismatic needle with a length of 0.6 mm. In addition to paceite, accompanying minerals include linarite , malachite , azurite , copper-containing smithsonite , cerussite , goethite , hematite and quartz .
See also
literature
- DE Hibbs, Uwe Kolitsch, P. Leverett, JL Sharpe, PA Williams: Hoganite and paceite, two new acetate minerals from the Potosi mine, Broken Hill, Australia . In: Mineralogical Magazine . tape 66 , no. 3 , June 2002, p. 459–464 , doi : 10.1180 / 0026461026630042 ( arizona.edu [PDF; 112 kB ; accessed on September 4, 2017]).
- Ray L. Frost, Anthony Musumeci: A spectroscopic and thermoanalytical study of the mineral hoganite . In: Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy . tape 67 , 2007, p. 48–57 , doi : 10.1016 / j.saa.2006.05.037 ( mineralogicalassociation.ca [PDF; 28 kB ; accessed on September 4, 2017]).
Web links
- Mineral Atlas: Hoganite
- Mindat - Hoganite
- Web mineral - Hoganite
- American-Mineralogist-Crystal-Structure-Database - Hoganite
Individual evidence
- ↑ a b c d e f g h i j k l DE Hibbs, Uwe Kolitsch, P. Leverett, JL Sharpe, PA Williams: Hoganite and paceite, two new acetate minerals from the Potosi mine, Broken Hill, Australia . In: Mineralogical Magazine . tape 66 , no. 3 , June 2002, p. 459–464 , doi : 10.1180 / 0026461026630042 ( arizona.edu [PDF; 112 kB ; accessed on September 4, 2017]).
- ↑ Hoganite . In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America . 2001 ( handbookofmineralogy.org [PDF; 67 kB ; accessed on September 4, 2017]).
- ^ Anthony Musumeci and Ray L. Frost: A spectroscopic and thermoanalytical study of the mineral Hoganite . In: Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy . tape 67 , no. 1 , 2007, p. 48–57 ( edu.au [PDF; 448 kB ; accessed on September 4, 2017]).
- ↑ Mindat - Hoganite