Prehnite and Quartz Crystals on Basalt Matrix – NBB 058

Measurements:  52 x 41 x 28 mm

Description:  Two undamaged balls of prehnite and numerous quartz crystals (of which some are damaged) sit on a matrix of basalt, quartz and epidote.

Many of the smaller quartz crystals have very small prehnite crystals attached to them.

Hidden in a forest of small quartz crystals, is another small ball of prehnite. 

The bottom of the specimen has been trimmed.

Weight of Specimen:  57.7 g

Chemical Composition:  Ca₂Al₂Si₃O₁₀(OH)₂  (prehnite)  
                                       SiO₂  (quartz)
                                       Ca₂Fe³⁺_2.25Al_0.75(SiO₄)₃(OH)  (epidote) 

Hardness on Mohs Scale:  (prehnite)  6-6.5
                                          (quartz)  7 
                                          (epidote) 7

Location:  Brandberg, Namibia.

Specimen Code:  NBB 058

US $ 65