![cushion cut sphalerite from Picos de Europa, Santander in Spain](https://www.patrickvoillot.com/wp-content/uploads/2021/03/sphalerite-coussin-espagne59-150x150.png)
![](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,Na)[(Si,Al)4O8]
sodium and calcium alumino-silicate
![](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
green
Other colors
white, grey, colourless, yellow
Color of streak
white
Luster
vitreous
Hardness
6.0 to 6.5
Density
2.70 to 0.00
Cleavage
perfect
Fracture
uneven
very small plane parts are observed on the fracture
![](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
transparent
Refractive index
1.560 - 1.580
Double refraction
0.010
weak biaxial (-)
visible double refraction
No
Dispersion
0,012
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
![](https://www.patrickvoillot.com/wp-content/uploads/2021/03/cristal-bytownite.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 is found in Madagascar, Mexico, El Salvador, South Korea, USA and Australia.
use in jewelry
faceted for collection
Venez visitez
notre site web
voillot-joaillier.fr
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