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Mixed Minerals

Sunday, 23 August 2020 07:00 PM

Introducing the "Mixed Minerals" gallery which is part of our New Additions galleries. This gallery contains mineral specimens for sale including eosphorite, gypsum, helvine, kaolinite, mimetite, and montgomeryite and more from places like Taquaral, Itinga, Minas Gerais, Brazil, Naica, Mun. de Saucillo, Chihuahua, Mexico, Sunnyside mine, Silverton, San Juan Co., Colorado, United States, St. Austell, Cornwall, England, San Pedro Corralitos, Chihuahua, Mexico, and Tip Top mine, Custer Co., South Dakota, United States.

Eosphorite

on Quartz - #AH53584
Locality
Taquaral, Itinga, Minas Gerais, Brazil 
Formula
Mn2+AlPO4(OH)2·H2
Availability
Available
Price
$55.00
Size
8 x 5 x 4 cm - Sm Cabinet 
Tagged
phosphate  

This is a very interesting specimen, mineralogically. All of the spongy mass has a goldish iridescence. I believe these to be Siderite or Calcite, which are elongated scalenohedral crysals grown in parallel. The bulk of the specimen is a large smoky Quartz crystal upon which neat little 1-4mm clusters of Eosphorite are grown.


Eosphorite

Formula
Mn2+AlPO4(OH)2·H2
Crystal System
Orthorhombic 
Crystal Habit
Massive - Fibrous, Prismatic, Striated 
Cleavage
Indistinct, None, None 
Luster
Vitreous - Resinous 
Color
light pink, yellow brown, light brown, light yellow, colorless 
Streak
white 
Class
Orthorhombic - Dipyramidal 
Fracture
Conchoidal - Uneven 
Hardness
Collection
Arnold G Hampson Collection

Gypsum

var. selenite - #WR53942
Locality
Naica, Mun. de Saucillo, Chihuahua, Mexico 
Formula
CaSO4·2H2
Availability
Available
Price
$75.00
Size
11 x 5 x 5 cm - Cabinet 

Sharp waterclear crystals of Gypsum, variety selenite, with the largest 6cm long. There are several large selenite crystals attached and also a second generation of tiny 2mm crystals over most of the specimen.


Gypsum

Formula
CaSO4·2H2
Crystal System
Monoclinic 
Crystal Habit
Tabular, Crystalline - Coarse, Massive - Fibrous 
Cleavage
Perfect, Distinct, Distinct 
Luster
Pearly 
Color
white, colorless, yellowish white, greenish white, brown 
Streak
white 
Class
Monoclinic - Prismatic 
Fracture
Fibrous 
Hardness
Collection
Willard L. Roberts Collection
On Dakota Matrix
Previously Sold Gypsum
On Dakota Matrix
Other Available Gypsum
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Mindat
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SOLD
Helvine - AH52955
Helvine - AH52955

Helvine

with Pyroxmangite - #AH52955
Locality
Sunnyside mine, Silverton, San Juan Co., Colorado, United States 
Formula
Mn2+4(BeSiO4)3
Availability
Sold
Size
3 x 3 x 2 cm - Thumbnail 
Tagged
beryllium  

Lemon yellow crystal grain of Helvine to 2mm in pink Pyroxmangite with some sulfides.


Helvine

Collection
A
On Dakota Matrix
Previously Sold Helvine
On Dakota Matrix
Other Available Helvine
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View Helvine
Mindat
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Kaolinite

after Orthoclase - #PD31698
Locality
St. Austell, Cornwall, England 
Formula
Al2Si2O5(OH)4 
Availability
Sold
Size
8.5 x 4.5 x 1.1 cm - Sm Cabinet 

White tabular crystal of formerly twinned Orthoclase completed replaced by Kaolinite.


Kaolinite

Formula
Al2Si2O5(OH)4 
Crystal System
Triclinic 
Crystal Habit
Earthy 
Cleavage
Perfect, None, None 
Luster
Earthy (Dull) 
Color
white, brownish white, grayish white, yellowish white, grayish green 
Streak
white 
Class
Triclinic - Pedial 
Fracture
Earthy 
Hardness
1.5-2 
Collection
Phillips Collection

Mimetite

#WR53945
Locality
San Pedro Corralitos, Chihuahua, Mexico 
Formula
Pb5(AsO4)3Cl 
Availability
Available
Price
$495.00
Size
11 x 7 x 4.5 cm - Cabinet 
Tagged
arsenate  

Yellow spheroidal crystals of Mimetite to 6mm across matrix. Like Mimetite from the Dry Gill mine, this locality has produced some of the world's best Mimetite. This specimen is no exception with great color and the abundance ot beautiful crystal groups. These guys are getting very hard to find.


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
Willard L. Roberts Collection
Mineralpedia
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On Dakota Matrix
Previously Sold Mimetite
On Dakota Matrix
Other Available Mimetite
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Mindat
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Montgomeryite

with carbonate apatite - #BN53931
Locality
Tip Top mine, Custer Co., South Dakota, United States 
Formula
Ca4MgAl4(PO4)6(OH)4·12H2
Availability
Sold
Size
18 x 16 x 5 cm - Cabinet 
Tagged
phosphate , pegmatite mineral  

This is a large cabinet specimen of red Montgomeryite crystals from 1 to 2mm, which are well-defined and with an overgrowth of Whitlockite in places. The matrix is a white to lilac carbonate apatite with more very tiny Whitlockite.


Montgomeryite

Formula
Ca4MgAl4(PO4)6(OH)4·12H2
Crystal System
Monoclinic 
Cleavage
Perfect, Indistinct, None 
Luster
Vitreous (Glassy) 
Color
colorless, yellowish, white, green, red 
Streak
white 
Class
Monoclinic - Prismatic 
Hardness
Collection
Dr. Buford Nichols Collection

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