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Euclase
Current inventory:  1 gem
 

Euclase

Chemistry:  BeAlSiO4(OH)  [Beryllium Aluminum Silicate Hydroxide]

Discovered in 1792;   IMA status: Valid (pre-IMA; Grandfathered).
The name Euclase is from the Greek eu meaning easy and klasis meaning fracture because of its easy cleavage.

 

Classification

   

   

Mineral Classification:

Silicates

Strunz 8th Ed. ID:

8/B.01-10

 

8 : Silicates
B : Nesosubsilicates, with anions unfamiliar to tetraheders, cations of octahedral and tetrahedral orientation [4/6]
01 : Euclase series

 

 

Crystal Data

   

   

Crystallography:

Monoclinic - Prismatic

Crystal Habit:

As prismatic crystals commonly morphologically complex, to 12 cm.

 

 

Physical Properties

   

 

Cleavage:

[010] Perfect, [110] and [001] Imperfect

Fracture:

Conchoidal

Tenacity:

Brittle

Moh's Hardness:

7.5

Density:

2.87 - 3.10 (g/cm3)

Radioactivity:

Not Radioactive

 

 

Optical Properties

   

   

Color:

Blue, Colorless, White, Light blue, Light green, Light Yellow.

Transparency:

Transparent to Translucent

Luster:

Vitreous (glassy)

Refractive Index:

1.652 - 1.671  Biaxial ( + )

Birefringence:

0.019 - 0.025

Dispersion:

Strong

Pleochroism:

Colorless

 

 

Occurances

   

   

Geological Setting:

The product of decomposition of beryl in pegmatites, and in low-temperature alpine veins

Type Locality:

Ouro PrÍto, Minas Gerais, Southeast Region, Brazil

Year Discovered:

1792

View mineral photos:

Euclase Mineral Photos and Locations

 

 

More Information

   

   

 

Mindat.org
Webmineral.com

 

 


Euclase is a very rare gem and is usually found as colorless or in shades of yellow, but is also rarely available in pale green, violet, pale blue and dark blue. The violet and blue material is extremely rare. Euclase is hard enough for jewelry but may be a bit brittle. The hardness (6.5 - 7.5) may be variable within a single crystal. Perfect one direction cleavage makes faceting difficult. Current sources are Brazil, Germany,
Mozambique, Russia and Zimbabwe.
 

  
Euclase gems for sale:

Euclase-001

Gem:

Euclase

Stock #:

EUCL-001

Weight:

1.41 ct

Size:

9.96 x 8.06 x 3.61 mm

Shape:

Fancy

Color:

Straw Yellow

Clarity:

VS2 -SI

Origin:

Southern Urals, Russia

Treatment:

None (natural)

Price:

$85.00

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

Euclase-001

This rare gem is from the Southern Urals, Russia. Euclase is very difficult to facet due to its easy, perfect cleavage. Even its name means easy fracture in Greek.


 

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