Click on a letter above to view the list of gems.    

  

 


Epididymite  
Current inventory:  0 gems
 

Epididymite

  
Epididymite is named from from the Greek words
epi for near, and didymus for twin referring to its dimorphous relation with Eudidymite.

Discovered in 1893;   IMA status: Valid (pre-IMA; Grandfathered)

 

Chemistry

 

 

Chemical Formula:

NaBeSi3O7(OH)

 

Sodium Beryllium Silicate Hydroxide

Molecular Weight:

245.26 gm

Composition:

Sodium

9.37 %

Na

12.64 %

Na2O

 

Beryllium

3.67 %

Be

10.20 %

BeO

 

Silicon

34.35 %

Si

73.49 %

SiO2

 

Hydrogen

0.41 %

H

3.67 %

H2O

 

Oxygen

52.19 %

O

 

 

 

 

100.00 %

 

100.00 %

= TOTAL OXIDE

 

 

Classification

   

   

Mineral Classification:

Silicates (Germanates)

Strunz 8th Ed. ID:

8/G.04-20

Nickel-Strunz 10th Ed. ID:

9.DG.55

 

9 : SILICATES (Germanates)
D : Inosilicates
G : Inosilicates with 3-periodic single and multiple chains

Related to:

Dimorphous with Eudidymite.

Synonyms:

Epidymite

 

 

Crystal Data

   

   

Crystallography:

Orthorhombic - Dipyramidal

Crystal Habit:

As pseudohexagonal crystals, tabular on {001}, also elongated along [010], to 6 cm. Micaceous, spherulitic, fine to coarse granular, porcelaneous massive.

Twinning:

On {001}, common, simple and polysynthetic; also as trillings.

 

 

Physical Properties

   

 

Cleavage:

Perfect on {001}, Distinct on {100}

Fracture:

Uneven to Conchoidal when massive

Tenacity:

Brittle

Moh's Hardness:

5.5

Density:

2.55 - 2.61 (g/cm3)

Luminescence:

None

Radioactivity:

Not Radioactive

 

 

Optical Properties

   

   

Color:

Colorless, White, also tinted Violet, Blue, or Yellow when finely crystalline

Transparency:

Transparent to Translucent 

Luster:

Vitreous on fractures, Pearly on cleavages

Refractive Index:

1.536 - 1.546  Biaxial ( + ) or ( - )

Birefringence:

0.0020

Dispersion:

Weak

 

 

Occurances

   

   

Geological Setting:

A late-stage mineral in nepheline syenite pegmatites.

Common Associations:

Aegirine, Albite, Analcime, Elpidite, Eudialyte, Leucophanite, Natrolite, Neptunite, Tugtupite

Common Impurities:

Al, Fe, Mg, Ca, K

Type Locality:

Narss‚rssuk pegmatite (Narsarsuk pegmatite), Narss‚rssuk (Narsarsuk), Igaliku (Igaliko), Narsaq, Kitaa (West Greenland) Province, Greenland

Year Discovered:

1893

View mineral photos:

Epididymite Mineral Photos and Locations

 

 

More Information

   

   

 

Mindat.org
Webmineral.com

 

 


Epididymite is a rare b
eryllium silicate mineral that is found in agpaitic pegmatite intrusions, an unusual igneous rock that is high in alkaline metals such as sodium and poor in silica. These intrusions also contain a large number of unusual elements such as beryllium, titanium, fluorine and rare earth metals but are typically low in aluminum and silica. Beryllium is a somewhat exotic element found in unusual concentrations in agpaite pegmatites allowing Epididymite to form.

Epididymite is found in locations that are famous agpaitic pegmatite sites like Kola Peninsula, Russia; Mont Saint-Hilaire, Canada; ArÝ Island, Langesundfjord, Norway and Narss‚rssuk, Greenland. These are all well known locations for rare silicate minerals. Other Epididymite locations include Vevja quarry, Tvedalen, Norway; VeznŠ, Czech Republic; near Saint-Amable, Quebec, Canada; near Quincy, Norfolk County, Massachusetts, USA; and large crystals on Mt. Malosa, Zomba district, Malawi.
 

  
Epididymite gems for sale:

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

 

I love Sarah