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Milarite
Current inventory:  0 gems
 

Milarite

Chemistry:  K2Ca4Al2Be4(Si24O60)∑(H2O)
[Hydrated Potassium Calcium Aluminum Beryllium Silicate]

Discovered in 1870;   IMA status: Valid (pre-IMA; Grandfathered).
Milarite was mistakenly named after what was thought to be its locality of discovery; Val Milar, Switzerland. However, Milarite was not discovered there, but instead was first found at Val Giuv, Tujetsch, Grischun, Switzerland. It was later also found at Val Milar.

 

Classification

   

   

Mineral Classification:

Silicates

Strunz 8th Ed. ID:

8/E.22-20

Nickel-Strunz 10th Ed. ID:

9.CM.05

 

9 : SILICATES (Germanates)
C : Cyclosilicates
M : [Si
6O18]12- 6-membered double rings (sechser-Doppelringe)

Related to:

Milarite - Osumilite Series

 

 

Crystal Data

   

   

Crystallography:

Hexagonal - Dihexagonal Dipyramidal

Crystal Habit:

Typically as well-formed hexagonal prisms, to 4 cm; as radial-fibrous aggregates and intergrowths.

Twinning:

None

 

 

Physical Properties

   

 

Cleavage:

[0001] Imperfect, [1120] Imperfect

Fracture:

Conchoidal to Uneven

Tenacity:

Brittle

Hardness (Mohs):

5.5 - 6.0

Density:

2.46 - 2.61 (g/cm3)

Luminescence:

Some specimens may be fluorescent

Radioactivity:

Barely Detectable; GRapi = 56.71 (Gamma Ray American Petroleum Institute Units)

 

 

Optical Properties

   

   

Color:

Colorless, White, Greenish White, Yellowish White

Transparency:

Transparent to Translucent, Opaque

Luster:

Vitreous

Refractive Index:

1.532 - 1.548  Uniaxial ( - ); anomalously Biaxial, sectored, with a Uniaxial core

Birefringence:

0.0030 - 0.0160

Dispersion:

n/a

Pleochroism:

n/a

 

 

Occurances

   

   

Geological Setting:

In alpine and low-temperature hydrothermal veins; in aplites, syenites, and granite pegmatites.

Common Associations:

Albite, Bavenite, Bertrandite, Beryl, Calcite, Chlorite, Fluorite, Minasgeraisite-(Y), Muscovite, Orthoclase, Phenakite, Quartz

Common Impurities:

Sodium (Na)

Type Locality:

Giuv Valley, Tujetsch (Tavetsch), Vorderrhein Valley, Grischun (Grisons; GraubŁnden), Switzerland

Year Discovered:

1870

View mineral photos:

Milarite Mineral Photos and Locations

 

 

More Information

   

   

 

Mindat.org
Webmineral.com

 

 


Milarite is a very rare gem. Crystals are colorless, pale green, yellowish green and yellowish. Most crystals are not facetable but occassional very small gemmy crystals are found. There are very few sources for Milarite crystals. These include St. Gotthard, Switzerland; Minas Gerais, Southeast Region, Brazil; Guanajuato, Mexico; Fujian Province, China; Arandis, Swakopmund District, Erongo Region, Namibia and Albany, Carrol County, New Hampshire, USA.
 
 

  
Milarite gems for sale:

We have not photographed our Milarite gems. Please check back soon.
 

 

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