Opal ("Fever Opal") red gem single finger-shaped cast of Prehnite

single finger-shaped cast of Prehnite replacing Anhydrite that is flaring out of the center of the specimen

much of the specimen has a coating of a secondary clay mineral

This crystal displays a fiery glowing red fluorescence when exposed to UV light

I cannot recall a comparable Bournonite from Machacamarca

One of the most well-known mineral species from Tsumeb is Smithsonite

Opal ("Fever Opal") red gem single finger-shaped cast of PrehniteWe picked up this stone from a friend who calls it "Fever Opal" as he said it wasn't "Fire Opal", per se, due to the mix of colors. The stone is about 50% colorless, but the other half shows a brilliant reddish orange hue creating a rarely seen two tone effect. Typically, the Fire Jelly Opals from Queretaro are a sold hue (yellow, orange or red), and a mixing of colors is rarely seen, especially in faceted material. This attractive "Emerald" cut gem