Opal Var Hyalite With Fluorapatite Var Staffelite

A very characteristic fine small cabinet specimen of colourless and vitreous Opal of the variety Hyalite.  This sits on top of Carbonate enriched Fluorapatite from the classic European location at Valeč in the Karlovy Vary Region of the Czech Republic. Bubbly Hyalite Opal forms a horseshoe shaped crescent with downward extension on white micro-botryoidal Carbonate-rich Fluorapatite, with a matrix of volcanic scoria.  Carbonate-rich Fluorapatite is sometimes given the variety name Staffelite but this name is now much less used.  The term ‘scoria’ describes any dark volcanic rock containing a proliferation of large gas bubbles or vesicles.  A splendid specimen from this occurrence at Valeč, the Carbonate-rich Fluorapatite displaying dull green fluorescence under LWUV light while some of the Hyalite fluoresces an even fainter green.