![green ludlamite crystal from Salsigne in France](https://www.patrickvoillot.com/wp-content/uploads/2021/03/ludlamite-cristaux-salsigne-france138-150x150.png)
![herderite crystal from Minas Gerais in Brazil](https://www.patrickvoillot.com/wp-content/uploads/2021/03/herderite-cristal-minas-gerais-bresil161-300x200.png)
herderite
![solid and cleavage like inclusions](https://www.patrickvoillot.com/wp-content/uploads/2021/03/inclusions-herderite-300x200.jpg)
solid and cleavage like inclusions
Detailed sheet
herderite
Its name honors the German mining engineer von Herder (1776-1838).
![](https://www.patrickvoillot.com/wp-content/uploads/2021/04/zoom-in.png)
![](https://www.patrickvoillot.com/wp-content/themes/astra-child/images/icon-image.png)
CHEMICAL CHARACTERISTICS
Ca,Be[PO4](F,OH)
basic calcium phosphate
![](https://www.patrickvoillot.com/wp-content/uploads/2021/04/zoom-in.png)
![](https://www.patrickvoillot.com/wp-content/themes/astra-child/images/icon-image2.png)
PHYSICAL CHARACTERISTICS
Main color
colourless
Other colors
blue, grey, yellow, green
pale color shades
Color of streak
white
Luster
vitreous
Hardness
5.0 to 5.5
Density
2.95 to 3.05
Cleavage
indistinct
Fracture
conchoidal
conchoidal
![](https://www.patrickvoillot.com/wp-content/uploads/2021/04/zoom-in.png)
![](https://www.patrickvoillot.com/wp-content/themes/astra-child/images/icon-image3.png)
OPTICAL PROPERTIES
Transparency
translucent, transparent
Refractive index
1.586 - 1.625
Double refraction
0.023
definite, biaxial (-)
visible double refraction
Yes
Dispersion
0,017(0.008)
Pleochroism
absent
Number of colors
1
Fluorescence
none
![](https://www.patrickvoillot.com/wp-content/uploads/2021/04/zoom-in.png)
![](https://www.patrickvoillot.com/wp-content/themes/astra-child/images/icon-image4.png)
CRYSTALS PROPERTIES
prismatic
![](https://www.patrickvoillot.com/wp-content/uploads/2021/03/cristal-herderite.gif)
crystals system
monoclinic
![](https://www.patrickvoillot.com/wp-content/uploads/2021/04/zoom-in.png)
![](https://www.patrickvoillot.com/wp-content/themes/astra-child/images/icon-image5.png)
OTHER INFORMATIONS
![](https://www.patrickvoillot.com/wp-content/uploads/2021/04/zoom-in.png)
![](https://www.patrickvoillot.com/wp-content/themes/astra-child/images/icon-image6.png)
APPROACHING GEMS
Exploited
sites
It occurs in beautiful crystals in Brazil (Paraiba, Governador Valadares), China (Jiangxi), Germany (Bavaria), England (Cornwall) United States (Maine, North Carolina, San Diego, California).
use in jewelry
it is cut in facets. It is a collection stone
Venez visitez
notre site web
voillot-joaillier.fr
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