Hyalite Opal on Schorl and Feldspar - NER 076 

Measurements:  46 x 33 x 32 mm 

Description:  Prolific aggregates of hyalite opal sit on a schorl and feldspar matrix.

It fluoresces beautifully under ultraviolet light. One photograph was taken in natural daylight.

The specimen has a few nicks and contact marks.

Chemical Composition:  SiO₂•1.5(H₂O)  (opal)
                                       NaFe²⁺₃Al₆Si₆O₁₈(BO₃)₃(OH)₄  (schorl)                                                KAlSi₃O₈  (feldspar) 

Hardness on Mohs Scale:  (opal)  5.5-6 
                                         (schorl )  7.5                                                                                       (feldspar)  6 - 6.5               

Location:  Erongo, Namibia.

Specimen Code:  NER 076