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Hemimorphite
Current inventory:  1 gem
 

Hemimorphite

Chemistry:  Zn4Si2O7(OH)2ˇ(H2O)   [Hydrated Zinc Silicate Hydroxide]

Discovered in 1853;   IMA status: Valid (pre-IMA; Grandfathered).
Hemimorphite is named in allusion to the hemimorphic form of the crystals.

 

Classification

   

   

Mineral Classification:

Silicates

Strunz 8th Ed. ID:

8/C.08-10

Nickel-Strunz 10th Ed. ID:

9.BD.10

 

9 : SILICATES (Germanates)
B : Sorosilicates
D : Si
2O7 groups, with additional anions; cations in tetrahedral [4] and greater coordination

Related to:

Hemimorphite - Junitoite Series

 

 

Crystal Data

   

   

Crystallography:

Orthorhombic - Pyramidal

Crystal Habit:

Commonly crystallized, thin tabular, striated, to 10 cm; doubly-terminated crystals show hemimorphism. Typically in sheaf-like or fan-shaped aggregates; stalactitic, mammillary, botryoidal; as compact fibrous and chalky coatings.

Twinning:

On [001], rare, with antilogous poles in contact.

 

 

Physical Properties

   

 

Cleavage:

[110] Perfect

Fracture:

Uneven to Conchoidal

Tenacity:

Brittle

Moh's Hardness:

4.5 - 5.0

Density:

3.40- 3.50 (g/cm3)

Luminescence:

May be bluish under SW UV.

Radioactivity:

Not Radioactive

Other:

Strongly Pyroelectric

 

 

Optical Properties

   

   

Color:

Colorless, white, grey, yellow, green to apple-green, blue, pink, purple, bluish grey, and brown from impurities

Transparency:

Transparent to Translucent

Luster:

Vitreous, Subpearly, Adamantine, rarely Silky

Refractive Index:

1.614 - 1.636  Biaxial ( + )

Birefringence:

0.022

Dispersion:

Strong; r > v

Pleochroism:

None

 

 

Occurances

   

   

Geological Setting:

A secondary mineral in the oxide zones of ore deposits and in veins and beds in stratified calcareous rocks.

Common Associations:

Anglesite, Aurichalcite, Calcite, Chrysocolla, Cerussite, Galena, Hydrozincite, Rosasite, Smithsonite, Sphalerite

Common Impurities:

Cu, Fe

Type Locality:

Baita Mining District (Baita Bihor; Rézbánya), Nucet, Bihor Co., Romania

Year Discovered:

1853

View mineral photos:

Hemimorphite Mineral Photos and Locations

 

 

More Information

   

   

 

Mindat.org
Webmineral.com

 

 


Hemimorphite is somewhat common as mineral specimen but rarely faceted due to lack of clean crystals. It is usually available as cabochons in beautiful shades of blue from Congo. There are several sources throughout the southwestern US and Mexico. However, faceted gems are only available from Mexico thus far and are usually colorless. Facetable crystals are rarely available from Mapimi, Durango, and Santa Eulalia, Chihuahua.
 

  
Hemimorphite gems for sale:

Hemimorphite-001

Gem:

Hemimorphite

Stock #:

HEMIM-001

Weight:

1.640 ct

Size:

6.39 x 6.42 x 4.30 mm

Shape:

Cut-corner Rectangle

Color:

Colorless

Clarity:

Translucent; I

Origin:

Mexico

Treatment:

None (natural)

Price:

$164.00    [ Make an offer ]

Pictures are of the actual gem offered for sale.
Gem images are magnified to show detail.

Hemimorphite-001

A very rare gem that is fairly large for the type.


 

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