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Herderite
Current inventory:  2 gems
 

Herderite

Chemistry:  CaBe(PO4)F  or  CaBe[(F,OH)|PO4]

Discovered in 1828;   IMA status: Valid (pre-IMA; Grandfathered).
Herderite is named after Sigmund August Wolfgang von Herder (1776-1838), a mining official in Freiburg, Saxony, Germany.

 

Classification

   

   

Mineral Classification:

Phosphates

Strunz 8th Ed. ID:

7/B.01-10

Nickel-Strunz 10th Ed. ID:

8.BA.10

 

8 : PHOSPHATES, ARSENATES, VANADATES
B : Phosphates, etc., with additional anions, without H
2O
A : With small and medium-sized cations

Related to:

Herderite-Hydroxylherderite Series. The Fluorine-dominant analogue of Hydroxylherderite. Herderite is isotypic with Datolite.

 

 

Crystal Data

   

   

Crystallography:

Monoclinic - Prismatic

Crystal Habit:

Stout prismatic crystals, thick tabular. Commonly pseudo-orthorhombic in aspect, rarely monoclinic; pseudo-hexagonal at times. Also occurs as botryoidal or spheroidal aggregates with a radial-fibrous structure.

Twinning:

On [100] or [001] as fishtail contact. Most crystals are twinned; however, some exhibit no outward signs of this morphology.

 

 

Physical Properties

   

 

Cleavage:

Imperfect, Fair; [110] Interrupted

Fracture:

Sub-Conchoidal

Tenacity:

Brittle

Hardness (Mohs):

5.0 - 5.5

Density:

2.95 - 3.02 (g/cm3)

Luminescence:

Fluoresces violet under UV; cathodoluminesces and phosphoresces pinkish orange under X-rays.

Radioactivity:

Not Radioactive

 

 

Optical Properties

   

   

Color:

Colorless, pale Yellow, Yellowish Green, light Green

Transparency:

Transparent to Translucent

Luster:

Vitreous

Refractive Index:

1.556 - 1.620  Biaxial ( - )

Birefringence:

0.033

Dispersion:

Moderate; r > v; 0.017

Pleochroism:

None

 

 

Occurances

   

   

Geological Setting:

Complex granitic pegmatites.

Common Associations:

n/a

Type Locality:

Sauberg Mine, Ehrenfriedersdorf, Erzgebirge, Saxony, Germany

Year Discovered:

1828

View mineral photos:

Herderite Mineral Photos and Locations

 

 

More Information

   

   

 

Mindat.org
Webmineral.com

 

 


Herderite is a very rare phosphate collectors gem. It is a very attractive gem but too soft for jewelry ware. It is found in many colors; yellow, green, blue, pink, pale violet and colorless. Currently, most material is from Brazil, although it is found in several localities around the world including pale yellow crystals from Maine, USA. The most notable occurances of gem quality crystals are Minas Gerais
, Brazil and Skardu District, Baltistan, Northern Areas, Pakistan.
 

  
Herderite gems for sale:

Herderite-001
please click on picture

Gem:

Herderite

Stock #:

HERD-001

Weight:

4.3260 ct

Size:

12.96 x 10.16 x 5.81 mm

Shape:

Trillion (modified)

Color:

Yellowish Green

Clarity:

Eye Clean, almost Loupe Clean

Origin:

Minas Gerais, Brazil

Treatment:

None (natural)

Price:

SOLD (but we have others)

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

Herderite-001
please click on picture

Please click on the pictures above for larger views.

A very rare collector's gem from Minas Gerais, Brazil. This beautiful gem is very large and clean for the type. It is very bright and has good color and great clarity.


Herderite-002

Gem:

Herderite

Stock #:

HERD-002

Weight:

2.1745 ct

Size:

7.81 x 7.74 x 4.25 mm

Shape:

Square/Emerald

Color:

Yellowish Green

Clarity:

Eye Clean to VVS

Origin:

Minas Gerais, Brazil

Treatment:

None (natural)

Price:

SOLD (but we have others)

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

Herderite-002

A very rare collector's gem from Minas Gerais, Brazil. This beautiful gem is very bright and has good color and clarity.


 

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