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Rare Minerals

Wednesday, 08 May 2024 03:00 PM

Introducing the "Rare Minerals" gallery which is part of our New Additions galleries. This gallery contains mineral specimens for sale including algodonite, ammonioborite, ammoniomagnesiovoltaite, bismutocolumbite, bobierrite, and brewsterite-sr and more from places like Mohawk mine, Keweenaw Co., Michigan, United States, Larderello, Pomarance, Pisa prov., Tuscany, Italy, Pécs-Vasas, Pécs dist., Baranya Co., Hungary, Danburitovaya vein, Malkhan pegmatite field, Krasnyi Chikoy, Krasnochikoysky dist., Zabaykalsky Krai, Russia, Kovdor Zheleznyi mine, Kovdor Massif, Murmansk Oblast, Russia, and Strontian, Argyllshire, Scotland.

Algodonite

#BAC64055
Locality
Mohawk mine, Keweenaw Co., Michigan, United States 
Formula
Cu1-xAsx; x = 1/7 
Availability
Sold
Size
3.4 x 3 x 1 cm - Miniature 
Tagged
sulfide , copper  

Brassy and iridescent Algondite mixed with Domeykite to be otherwise called "Mohawkite".


Algodonite

Formula
Cu1-xAsx; x = 1/7 
Crystal System
Hexagonal 
Crystal Habit
Massive - Granular, Tarnishes 
Cleavage
None, None, None 
Luster
Metallic 
Color
gray, silver white, steel gray, tarnishes dull bronze 
Class
Hexagonal - Dihexagonal Dipyramidal 
Fracture
Sub Conchoidal 
Hardness
Collection
William & Anne Cook Collection

Ammonioborite

#BAC64087
Locality
Larderello, Pomarance, Pisa prov., Tuscany, Italy 
Formula
(NH4)3B15O20(OH)8·4H2
Availability
Sold
Size
3.5 x 2.2 x 2.5 cm - Miniature 

This is mostly a chalky mass of Ammonioborite.


Ammonioborite

Formula
(NH4)3B15O20(OH)8·4H2
Crystal System
Monoclinic 
Cleavage
None, None, None 
Color
white 
Streak
white 
Class
Monoclinic - Prismatic 
Hardness
Collection
William & Anne Cook Collection

Ammoniomagnesiovoltaite

#BAC64065
Locality
Pécs-Vasas, Pécs dist., Baranya Co., Hungary 
Formula
(NH4)2Mg2+5Fe3+3Al(SO4)12 18H2
Availability
Sold
Size
0.5 x 0.4 x 0.4 cm - Thumbnail 
Special Info
Type Locality 

White crusts. Ammoniomagnesiovoltaite is an efflorescent product deposited on burning carbonaceous material in waste dumps at coal mines. There are three small 5-6mm pieces in a capsule.


Collection
William & Anne Cook Collection
Special Info
Type Locality

Bismutocolumbite

#BAC64095
Locality
Danburitovaya vein, Malkhan pegmatite field, Krasnyi Chikoy, Krasnochikoysky dist., Zabaykalsky Krai, Russia 
Formula
BiNbO4 
Availability
Sold
Size
4.2 x 3.7 x 2.5 cm - Miniature 
Tagged
pegmatite mineral  

Supurb glassy pink prismatic crystals throughout vuggy specimen. The crystals are generally from 1 to 2mm. Three sides are sawed flat, probably for analytical work.


Bismutocolumbite

Formula
BiNbO4 
Crystal System
Orthorhombic 
Cleavage
Perfect, None, None 
Luster
Sub Metallic 
Color
black 
Streak
yellowish brown 
Class
Orthorhombic - Dipyramidal 
Hardness
5.5 
Collection
William & Anne Cook Collection

Bobierrite

#64063
Locality
Kovdor Zheleznyi mine, Kovdor Massif, Murmansk Oblast, Russia 
Formula
Mg3(PO4)2·8H2
Availability
Sold
Size
4.5 x 4.5 x 4 cm - Miniature 
Tagged
phosphate  

Large divergent crystal groups, the largest to 2cm with several smaller groups around matrix. Excellent specimen. Bobierrite is a member of the Vivianite group and the crystals show it.


Bobierrite

Formula
Mg3(PO4)2·8H2
Crystal System
Monoclinic 
Cleavage
Perfect, None, None 
Luster
Vitreous (Glassy) 
Color
colorless, gray, white 
Streak
white 
Class
Monoclinic - Prismatic 
Hardness
2-2.5 
Collection
William & Anne Cook Collection

Brewsterite-Sr

#CL64026
Locality
Strontian, Argyllshire, Scotland 
Formula
Sr(Al2Si6)O16·5H2
Availability
Available
Price
$125.00
Size
6 x 7 x 3 cm - Sm Cabinet 

Colorless prismatic crystals to 3mm. These are choice crystals.


Brewsterite-Sr

Formula
Sr(Al2Si6)O16·5H2
Crystal System
Monoclinic 
Crystal Habit
Prismatic 
Cleavage
Perfect, None, None 
Luster
Vitreous (Glassy) 
Color
white, yellowish white, gray. 
Streak
white 
Class
Monoclinic - Prismatic 
Hardness
Collection
Chet S. Lemanski, Jr. Collection

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