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Rare Mineral Specimens

Wednesday, 17 August 2022 06:00 PM

Introducing the "Rare Mineral Specimens" gallery which is part of our New Additions galleries. This gallery contains mineral specimens for sale including gold, humite, mimetite, monticellite, newberyite, and simpsonite and more from places like Harvard mine, Jamestown, Tuolumne Co., California, United States, Mania, Island of Madagascar, Dry Gill mine, Caldbeck Fells, Cumbria, England, Crestmore, Riverside Co., California, United States, Skipton Caves, Mt. Widderin, Skipton, Victoria, Australia, and Governador Valadares, Minas Gerais, Brazil.

Gold

#58182
Locality
Harvard mine, Jamestown, Tuolumne Co., California, United States 
Formula
Au 
Availability
Available
Price
$50.00
Size
0.5 x 0.3 x 0.3 cm - Thumbnail 
Tagged
native element  

For nice leaf Gold specimens each to about 3 to 5mm.


Gold

Formula
Au 
Crystal System
Isometric 
Crystal Habit
Arborescent, Platy, Granular 
Cleavage
None, None, None 
Luster
Metallic 
Color
yellow, pale yellow, orange, yellow white, reddish white 
Streak
yellow 
Class
Isometric - Hexoctahedral 
Fracture
Hackly 
Hardness
2.5-3 
Mineralpedia
View Goldmanite
On Dakota Matrix
Previously Sold Gold
On Dakota Matrix
Other Available Gold
WebMineral
View Gold
Mindat
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Humite

#RS59041
Locality
Mania, Island of Madagascar 
Formula
Mg7(SiO4)3(F,OH)2 
Availability
Sold
Size
3 x 3 x 2.5 cm - Thumbnail 

A good, rich specimen with crystal grains of Humite from 1 to 4mm in white Calcite (marble?). This was an old Southwest Scientific Company specimen, which placed the locality at Mania, Madagascar. But Mania is a river. I couldn't reconcile this locality with any other locality for Humite in Madagascar. As such, I stuck with the labeled locality in hopes that somebody out there has any information. Mindat only list one locality in Madagascar.


Humite

Formula
Mg7(SiO4)3(F,OH)2 
Crystal System
Orthorhombic 
Cleavage
Poor, None, None 
Luster
Vitreous (Glassy) 
Color
brown, yellow, white, dark orange 
Streak
white 
Class
Orthorhombic - Dipyramidal 
Fracture
Conchoidal - Uneven 
Hardness
6-6.5 
Collection
RC Stamberg Collection
Mineralpedia
View Humite
On Dakota Matrix
Previously Sold Humite
On Dakota Matrix
Other Available Humite
WebMineral
View Humite
Mindat
View Humite

Mimetite

var. campylite - #RS59044
Locality
Dry Gill mine, Caldbeck Fells, Cumbria, England 
Formula
Pb5(AsO4)3Cl 
Availability
Available
Price
$60.00
Size
6.5 x 7 x 3.5 cm - Sm Cabinet 
Tagged
arsenate  

Caramel colored "curled" Mimetite crystals to 6mm.


Mimetite

Formula
Pb5(AsO4)3Cl 
Crystal System
Hexagonal 
Crystal Habit
Reniform, Globular, Prismatic 
Cleavage
Imperfect, None, None 
Luster
Adamantine - Resinous 
Color
white, yellow, orange, brown, red 
Streak
white 
Class
Hexagonal - Dipyramidal 
Fracture
Brittle - Conchoidal 
Hardness
3.5-4 
Collection
RC Stamberg Collection
Mineralpedia
View Mimetite
On Dakota Matrix
Previously Sold Mimetite
On Dakota Matrix
Other Available Mimetite
WebMineral
View Mimetite
Mindat
View Mimetite

Monticellite

in Calcite - #RS59049
Locality
Crestmore, Riverside Co., California, United States 
Formula
CaMgSiO4 
Availability
Sold
Size
6 x 5 x 4 cm - Sm Cabinet 

Light orange to tan crystal grains in blue Calcite.


Monticellite

Formula
CaMgSiO4 
Crystal System
Orthorhombic 
Crystal Habit
Crystalline - Fine, Prismatic 
Cleavage
Indistinct, None, None 
Luster
Vitreous (Glassy) 
Color
colorless, greenish gray, gray 
Streak
white 
Class
Orthorhombic - Dipyramidal 
Fracture
Brittle 
Hardness
Collection
RC Stamberg Collection

Newberyite

#RS59054
Locality
Skipton Caves, Mt. Widderin, Skipton, Victoria, Australia 
Formula
Mg(PO3OH)·3H2
Availability
Available
Price
$75.00
Size
0.5 x 0.4 x 0.3 cm - Thumbnail 
Tagged
phosphate  

A fantastic multi-faced crystal.


Newberyite

Formula
Mg(PO3OH)·3H2
Crystal System
Orthorhombic 
Cleavage
Perfect, Indistinct, None 
Luster
Vitreous (Glassy) 
Color
colorless, gray brown, grayish 
Streak
white 
Class
Orthorhombic - Dipyramidal 
Fracture
Brittle - Uneven 
Hardness
3-3.5 
Collection
RC Stamberg Collection

Simpsonite

#RS59053
Locality
Governador Valadares, Minas Gerais, Brazil 
Formula
Al4Ta3O13(OH) 
Availability
Sold
Size
1 x 0.7 x 0.4 cm - Thumbnail 
Tagged
pegmatite mineral  

A partial orange tabular crystal. Rare!


Simpsonite

Formula
Al4Ta3O13(OH) 
Crystal System
Trigonal 
Crystal Habit
Euhedral Crystals, Prismatic, Striated 
Cleavage
None, None, None 
Luster
Vitreous - Adamantine 
Color
brownish yellow, colorless, white, light brown, light yellow 
Streak
white 
Class
Trigonal - Pyramidal 
Fracture
Brittle - Conchoidal 
Hardness
7-7.5 
Collection
RC Stamberg Collection

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