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Rare Minerals

Sunday, 09 January 2022 06:00 PM

Introducing the "Rare Minerals" gallery which is part of our New Additions galleries. This gallery contains mineral specimens for sale including hureaulite, hydroboracite, langbeinite, lithiophorite, mitscherlichite, and mosesite and more from places like Fletcher mine, Groton, Grafton Co., New Hampshire, United States, Terry Borate mine, Death Valley, Inyo Co., California, Carlsbad Potash dist., Eddy Co., New Mexico, United States, Gloucester, Postmasburg, Northern Cape Province, South Africa, Atrio del Cavallo, Mt Vesuvius, Somma-Vesuvius Complex, Naples, Campania, Italy, and Terlingua dist., Brewster Co., Texas, United States.

Hureaulite

with Rockbridgeite - #BW57390
Locality
Fletcher mine, Groton, Grafton Co., New Hampshire, United States 
Formula
Mn2+5(PO4)2(PO3OH)2·4H2
Availability
Sold
Size
6 x 4.5 x 2 cm - Sm Cabinet 
Tagged
phosphate , pegmatite mineral  

The red Hureautlite really stands out in the photos. Tone it down just a little bit and that's the real color. But it's still a good rich red. On this specimen the Hureaulite doesn't form any free-standing crystals, it just a mass with embedded crystals. It is associated with black divergent crystals of Rockbridgeite.


Hureaulite

Formula
Mn2+5(PO4)2(PO3OH)2·4H2
Crystal System
Monoclinic 
Crystal Habit
Massive, Compact, Fibrous 
Cleavage
Distinct, None, None 
Luster
Vitreous - Greasy 
Color
red, white, grayish white, yellowish white, reddish white 
Streak
white 
Class
Monoclinic - Prismatic 
Fracture
Brittle - Uneven 
Hardness
Collection
Bill Wilson Collection

Hydroboracite

#BW57381
Locality
Terry Borate mine, Death Valley, Inyo Co., California 
Formula
CaMg[B3O4(OH)3]2·3H2
Availability
Sold
Size
4.5 x 2.7 x 2 cm - Miniature 

Colorless to white radiating bladed crystals to 1.5cm. A very good specimen.


Hydroboracite

Formula
CaMg[B3O4(OH)3]2·3H2
Crystal System
Monoclinic 
Crystal Habit
Fibrous, Foliated 
Cleavage
Perfect, None, None 
Luster
Vitreous - Silky 
Color
colorless, greenish, white, light brown, wine yellow 
Streak
white 
Class
Monoclinic - Prismatic 
Hardness
Collection
Bill Wilson Collection
SOLD
Langbeinite - BW57393
Langbeinite - BW57393

Langbeinite

#BW57393
Locality
Carlsbad Potash dist., Eddy Co., New Mexico, United States 
Formula
K2Mg2(SO4)3 
Availability
Sold
Size
6 x 1.5 x 1.5 cm - Sm Cabinet 
Special Info
Type Locality 

White masses to 1cm in vial.


Langbeinite

Formula
K2Mg2(SO4)3 
Crystal System
Isometric 
Cleavage
None, None, None 
Luster
Vitreous (Glassy) 
Color
colorless, violet, greenish, gray, yellowish 
Streak
white 
Class
Isometric - Tetartoidal 
Fracture
Brittle - Conchoidal 
Hardness
3.5-4 
Collection
Bill Wilson Collection
Special Info
Type Locality

Lithiophorite

#BW57371
Locality
Gloucester, Postmasburg, Northern Cape Province, South Africa 
Formula
(Al,Li)Mn4+O2(OH)2 
Availability
Sold
Size
7.5 x 5.5 x 5 cm - Sm Cabinet 

These are exceptional, choice crystals of Lithiophorite. Lithiophorite was previously considered to be a type of wad or psilomelane. But in 1932 Ramsdell determined it to be a distinct mineral giving a unique XRD pattern which contained lithium. The Lithiophorite from the Mn deposits in Postmasburg have been known since 1943. I am not sure when the crystals of this size have been found, but they are unlike any other deposit. They are usually found as dendrites, spherulitic or botryoidal masses. These crystals are dull black on the surface but shiny and very reflective on the cleavages. They also show v-shaped twinning on the fresh surface. The aggregate crystals are oddly-shaped rounded or spool-like masses. I can speculate that these crystals from this locality are the best. Some references are: J. E. De Villiers and Jeffrey Post


Lithiophorite

Formula
(Al,Li)Mn4+O2(OH)2 
Crystal System
Trigonal 
Crystal Habit
Botryoidal 
Cleavage
Perfect, None, None 
Luster
Metallic - Dull 
Color
bluish black, black 
Streak
blackish gray 
Class
Trigonal - Hexagonal Scalenohedral 
Fracture
Sectile 
Hardness
2.5-3 
Collection
Bill Wilson Collection

Mitscherlichite

#BW57384
Locality
Atrio del Cavallo, Mt Vesuvius, Somma-Vesuvius Complex, Naples, Campania, Italy 
Formula
K2CuCl4·2H2
Availability
Sold
Size
4 x 3 x 1.5 cm - Miniature 
Tagged
copper  
Special Info
Type Locality 

This is the type locality for this rather rare copper halide. The Mitscherlichite is pulverulent blue. 


Mitscherlichite

Formula
K2CuCl4·2H2
Crystal System
Tetragonal 
Crystal Habit
Crystalline - Fine 
Luster
Vitreous (Glassy) 
Color
green, green blue 
Class
Tetragonal - Ditetragonal Dipyramidal 
Hardness
2.5 
Collection
Bill Wilson Collection
Special Info
Type Locality

Mosesite

#54803
Locality
Terlingua dist., Brewster Co., Texas, United States 
Formula
Hg2N(Cl,SO4,MoO4,CO3)·H2
Availability
Sold
Size
4 x 2 x 2 cm - Miniature 
Special Info
Type Locality 

Yellow crystalline area (1.2 x 0.7cm) of Mosesite.


Mosesite

Formula
Hg2N(Cl,SO4,MoO4,CO3)·H2
Crystal System
Isometric 
Crystal Habit
Cubic Crystals 
Cleavage
Indistinct, None, None 
Luster
Adamantine 
Color
yellow, light green, olive green 
Streak
light yellow 
Class
Isometric - Hextetrahedral 
Fracture
Brittle - Uneven 
Hardness
3-4 
Special Info
Type Locality
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