Prehnite Ball on Calcite Crystals, on Matrix - NBB 222

Measurements:  43 x 27 x 26 mm        

Description:  The specimen consistes of a lovely ball of bladed prehnite (20 x 19 mm) sitting on calcite crystals which, in turn, sit on a matrix of basalt rock. One small, clear quartz crystal (± 7 mm long) sits alongside the prehnite.

Damage appears to be limited to the edges of the specimen only, and a flaw to the side of the prehnite ball (middle two images on left).

Weight of Specimen:  24.9 g

Chemical Composition:  Ca₂Al₂Si₃O₁₀(OH)₂  (prehnite)  
                                       SiO₂  (quartz)  
                                       CaCO₃  (calcite) 
                                 
Hardness on Mohs Scale:   (prehnite) 6-6.5
                                           (quartz)  7                                                                                             (calcite)  3 

Location:  Brandberg, Namibia.

Specimen Code:  NBB 222

US $ 65

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