Spinel

The Luc Yen mine in Yenbai Province, Vietnam, works a deposit rich in various gem minerals, one of which is the magnesium aluminium oxide Spinel.  Although this is a miniature, the Spinel crystals are certainly not!  Forming as a partly intergrown group in a white marble, the larges prism measures 2.3 cm long and displays magnificent twinning marked by deep re-entrant angled faces.  The Spinel crystals are translucent cranberry-plum mauve with a waxy lustre and slightly rounded edges all over.  Placed under LWUV the Spinel fluoresces orange red against the fluorescent white marble.  If investigating its UV characteristics, be sure to let your LWUV lamp warm-up for a couple of minutes.  At first this specimen did not appear to fluoresce, but given two minutes it was motoring, to use a technical expression! A stunning Spinel in Marble from Luc Yen, Vietnam.