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Mixed Minerals

Friday, 08 October 2021 12:00 PM

Introducing the "Mixed Minerals" gallery which is part of our New Additions galleries. This gallery contains mineral specimens for sale including ellenbergerite, olmsteadite, pumpellyite-(mg), and quartz and more from places like Case Parigi, Martiniana Po, Cuneo, Piedmont, Italy, Big Chief mine, Pennington Co., South Dakota, United States, Isle Royale, Lake Superior, Keweenaw Co., Michigan, United States, and Monte Rosso, Castlenuovo Monti, Reggio Emilia, Italia.

Ellenbergerite

#56661
Locality
Case Parigi, Martiniana Po, Cuneo, Piedmont, Italy 
Formula
Mg6(Mg,Ti,Zr,□)2(Al,Mg)6Si8O28(OH)10 
Availability
Available
Price
$85.00
Size
3.5 x 3 x 1.5 cm - Miniature 
Special Info
Type Locality 

Ellenbergerite, a very rare titanium-zirconium silicate, was described in 1984 from this locality. It is found no where else on Earth except this locality and a few nearby localites. It typically occurs as inclusions in Pyrope garnets, but rarely as single crystals like this specimen. The largest crystal is 1.5mm at the lower arrow. 


Ellenbergerite

Formula
Mg6(Mg,Ti,Zr,[box])2(Al,Mg)6Si8O28(OH)10 
Crystal System
Hexagonal 
Cleavage
None, None, None 
Luster
Vitreous (Glassy) 
Color
colorless, purple, lilac 
Streak
white 
Class
Hexagonal - Pyramidal 
Hardness
6.5 
Special Info
Type Locality

Olmsteadite

#56664
Locality
Big Chief mine, Pennington Co., South Dakota, United States 
Formula
KFe2+2NbO2(PO4)2·2H2
Availability
Sold
Size
4 x 2 x 1.5 cm - Miniature 
Tagged
phosphate , pegmatite mineral  
Special Info
Type Locality 

Deep, deep red short prismatic-tabular crystals in a 1mm cluster. There are four or five individual crystals in the cluster. The matrix is granular Siderite with a little Quartz and minor sulfides. Olmsteadite has been thus far found only in the Black Hills at three pegmatites: The White Cap mine, the Hesnard mine, and the Big Chief mine. The Big Chief is the type locality. Curiously enough all three are in the Keystone district and fairly close to each other. It forms presumably in the presence of Columbite.


Olmsteadite

Formula
KFe2+2NbO2(PO4)2·2H2
Crystal System
Orthorhombic 
Crystal Habit
Prismatic 
Cleavage
Good, Good, None 
Luster
Subadamantine 
Color
brown, reddish brown, black 
Streak
olive green 
Class
Orthorhombic - Pyramidal 
Fracture
Brittle 
Hardness
Special Info
Type Locality

Pumpellyite-(Mg)

var. chlorastrolite - #56665
Locality
Isle Royale, Lake Superior, Keweenaw Co., Michigan, United States 
Formula
Ca2MgAl2(SiO4)(Si2O7)(OH)2·H2
Availability
Sold
Size
0.6 x 0.3 x 0.3 cm - Thumbnail 

Polished cabs of this rare, weird Pumpellyite-(Mg) variety chlorastrolite. 


Pumpellyite-(Mg)

Formula
Ca2MgAl2(SiO4)(Si2O7)(OH)2·H2
Crystal System
Monoclinic 
Crystal Habit
Spherical, Fibrous, Massive - Lamellar 
Cleavage
Good, Good, None 
Luster
Vitreous (Glassy) 
Color
blue green, olive green, brown 
Streak
white 
Class
Monoclinic - Prismatic 
Fracture
Sub Conchoidal 
Hardness
5.5 
Collection
Arnold G Hampson Collection

Quartz

in Anhydrite - #52508
Locality
Monte Rosso, Castlenuovo Monti, Reggio Emilia, Italia 
Formula
SiO2 
Availability
Available
Price
$60.00
Size
7 x 2.5 x 3.5 cm - Sm Cabinet 

Two doubly terminated deep smoky almost black Quartz ( 1cm and 1.3cm) crystal exposed from Anhydrite matrix. These recently made the front cover of Lapis (Jan. 2020). Please see provenance tab for copy photo of Lapis. Ex. Renato Pagano collection. Prov. tab cover copy of Lapis included. 


Quartz

Formula
SiO2 
Crystal System
Trigonal 
Crystal Habit
Crystalline - Coarse, Druse, Crystalline - Fine 
Cleavage
Indistinct, None, None 
Luster
Vitreous (Glassy) 
Color
brown, colorless, violet, gray, yellow 
Streak
white 
Class
Trigonal - Trapezohedral 
Fracture
Conchoidal 
Hardness
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