Ulrichite

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Ulrichite
Ulrichite-27441.jpg
Tufts of greenish ulrichite in granite from the granite quarry Lake Boga , Victoria (Australia) (5.3 cm × 4.4 cm × 3.8 cm)
General and classification
other names

IMA 1988-006

chemical formula CaCu [UO 2 | (PO 4 ) 2 ] • 4H 2 O
Mineral class
(and possibly department) 		Phosphates, arsenates and vanadates
System no. to Strunz
and to Dana 		8.EA.15 ( 8th edition : VII / E.02)
40.02a.33.01
Crystallographic Data
Crystal system monoclinic
Crystal class ; symbol monoclinic prismatic; 2 / m
Room group (no.) C 2 / m (No. 12)
Lattice parameters a  = 12.79  Å ; b  = 6.85 Å; c  = 13.02 Å
β  = 91.0 °
Formula units Z  = 4
Twinning after {100}
Physical Properties
Mohs hardness 3 to 3.5
Density (g / cm 3 ) calculated: 3.71
Cleavage no
colour light apple green, lime green
Line color White
transparency transparent to translucent
shine Glass gloss
radioactivity very strong
Crystal optics
Refractive indices n α  = 1.622
n γ  = 1.634
Birefringence δ = 0.012
Optical character biaxial negative
Other properties
Chemical behavior Easily soluble in dilute HCl and HNO 3
Special features dark yellow fluorescence

Ulrichite is a very rare mineral from the mineral class of "phosphates, arsenates and vanadates". It crystallizes in the monoclinic crystal system with the chemical composition CaCu [UO 2 | (PO 4 ) 2 ] · 4H 2 O and thus is a hydrous calcium - copper - uranyl - phosphate .

Ulrichite is transparent to translucent and only develops very small, needle-like crystals up to about one millimeter in length and 0.05 millimeter thick and with a glass-like sheen on the surfaces. The crystals are typically arranged in radial, tufted aggregates . Tabular prisms and occasionally crystal twins have also been observed. The color of the mineral varies between light apple green and lime green , but its stroke color is always white.

With a Mohs hardness of 3 to 3.5, ulrichite is one of the medium-hard minerals that can be scratched with a copper coin , similar to the reference mineral calcite (3).

Etymology and history

Ulrichite was first discovered in the granite quarry about 10 kilometers south-southwest of Lake Boga and 17 kilometers south of Swan Hill in the Australian state of Victoria and described in 1988 by WD Birch, WG Mumme and ER Segnit, who named the mineral after the German-Australian geologist and mineralogist Georg Heinrich Friedrich Ulrich (1830–1900) named.

Type material of the mineral is kept in the Museum Victoria in Melbourne (catalog no. M38576).

classification

Already in the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , ulrichite belonged to the mineral class of "phosphates, arsenates and vanadates" and there to the department of "uranyl phosphates / arsenates and uranyl vanadates", where together with abernathyite , bassetite , Chernikovit , Lehnerit , Metaankoleit , Metaautunit , Metaheinrichit , Metakahlerit , Metakirchheimerit , Metalodèvit , Metanatroautunit , Metanováčekit , Metatorbernit , Metauranocircit , Metauranospinit , Metazeunerit , Natrouranospinit , Pseudoautunit , Uramarsit , Uramphit the "Metaautunit group" with the system number. VII / E.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 Ulrichite in the "Uranylphosphate and Arsenate" department. However, this is further subdivided according to the molar ratio of the uranyl compounds to the phosphate, arsenate or vanadate complex (RO 4 ), so that the mineral can be found in the sub-section "UO 2  : RO 4  = 1: 2" according to its composition , where it is the only member of the unnamed group 8.EA.15 .

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns Ulrichite to the class of "phosphates, arsenates and vanadates" and there in the department of "water-containing phosphates, etc.". Here he is the only member / together with in the unnamed group 40.02a.33 within the subdivision "Water-containing phosphates etc., with A 2+ (B 2+ ) 2 (XO 4 ) × x (H 2 O), with ( UO 2 ) 2+ ”.

Crystal structure

Ulrichite crystallizes monoclinically in the space group C 2 / m (space group no. 12) with the lattice parameters a  = 12.79  Å ; b  = 6.85 Å; c  = 13.02 Å and β = 91.0 ° as well as four formula units per unit cell .

The crystal structure of Ulrichit consists of edge-sharing calcium and UO 2 + 5 - polyhedra , which PO 4 - tetrahedra are connected to parallel layers (100). These layers are held together by CuO 4 and H 2 O molecules.

properties

The mineral is very radioactive due to its uranium content of up to 37.45% . Taking into account the natural decay chains or of existing decay products which is specific activity of 67.03 k Bq stated / g (compared to natural potassium 0.0312 kBq / g).

Under short-wave UV light , some Ulrichites show a strong, dark yellow fluorescence , similar to that of neon-colored highlighters .

Ulrichite is easily soluble in dilute hydrochloric acid (HCl) and nitric acid (HNO 3 ).

Education and Locations

Ulrichite forms secondarily in miarolitic cavities of pegmatitic granites . As accompanying minerals may include Chalkosiderit , Cyrilovit , fluorapatite , Libethenit , Sampleit , Saléeit , Torbernit and turquoise occur.

So far (as of 2014) the mineral could only be detected at its type locality Lake Boga in Australia.

Precautions

Due to the strong radioactivity of the mineral, mineral samples from Ulrichit should only be kept in dust- and radiation-tight containers, but especially never in living rooms, bedrooms or work rooms. Absorption into the body ( incorporation , ingestion ) should also be prevented in any case and, for safety, direct body contact should be avoided and respiratory protection mask and gloves should be worn when handling the mineral .

See also

literature

  • WD Birch, WG Mumme, ER Segnit: Ulrichite: a new copper calcium uranium phosphate from Lake Boga, Victoria, Australia. In: Australian Mineralogist. Volume 3, 1988, pp. 125-131.
  • John Leslie Jambor , Edward S. Grew: New Mineral Names. In: American Mineralogist. Volume 75, 1990, pp. 240–246 ( PDF 694.1 kB )
  • Uwe Kolitsch , G. Giester: Revision of the crystal structure of ulrichite, CaCu 2+ (UO 2 ) (PO 4 ) 2 · 4H 2 O. In: Mineralogical Magazine. Volume 65, 2001, pp. 717-724 ( PDF 240 kB )

Web links

Commons : Ulrichite  - collection of images, videos and audio files

Individual evidence

  1. ↑ a b c d e Hugo Strunz , Ernest H. Nickel: Strunz Mineralogical Tables . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p.  523 .
  2. ↑ Ulrichite , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 65.2 kB )
  3. ^ WD Birch, WG Mumme, ER Segnit: Ulrichite: a new copper calcium uranium phosphate from Lake Boga, Victoria, Australia. In: Australian Mineralogist. Volume 3, 1988, pp. 125-131.
  4. ↑ Webmineral - Ulrichite
  5. ^ Mindat - Ulrichite
  6. ↑ Find location list for Ulrichite in the Mineralienatlas and in Mindat