Mineral "Hyalite & Staffelite"
Valeč, Karlovy Vary Region, Czech Republic, private collection from Netherlands.
Hyalite is a transparent form of opal with a glassy lustre. It may exhibit an internal play of colors if natural inclusions are present. It is also called Muller's glass, water opal, and jalite. Müller's glass is named after its discoverer, Franz-Joseph Müller von Reichenstein.
Carbonate-rich Fluorapatite is sometimes given the variety name Staffelite but this name is now much less used. Fluorapatite, common phosphate mineral, a calcium fluoride phosphate. Fluorapatite is a hard crystalline solid. Although samples can have various color (green, brown, blue, yellow, violet, or colorless), the pure mineral is colorless, as expected for a material lacking transition metals.
Absolutely stunning, glass clear and vitreous bead like Hyalite forms a tower shaped crescent with downward extension on white micro-botryoidal Carbonate-rich Staffelite, with a matrix of volcanic scoria. The condition of the sample is excellent. Age-related wear, fractures and minor cracks may appear. Dirt and dust. Size approx. 3,7cm x 4,6cm x 3,8cm. Weight c. 52g.