Prehnite, Calcite and Quartz Crystals on Matrix - NBB 157

Measurements:  41 x 32 x 20 mm

Description:  A specimen consisting of lovely green bladed prehnite crystals and a few calcite crystals, with a quartz crystal (with only a touch of amethyst colouring and a few hematitie specks) sticking through the mass of prehnite blades near the side of the specimen. 

The prehnite blades are partly covered with a sprinkling of very minute crystals of some white mineral (?) that almost looks like snow :-)  The small matrix is (?)sandstone. The specimen has a few traces of epidote.

Damage is limited to a few very minute nicks to the quartz crystal, otherwise only some damage to bottom and edges of specimen.

Weight of Specimen:  24.5 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 157   

US $ 30