Opal from Virgin Valley, USA

Opal from Virgin Valley, Humboldt County, Nevada, USA

Common 'honey' Opal specimens from Virgin Valley, Nevada, USA.

While these opals do not show any play of colour, they are fluorescent under 365nm ultraviolet light. They seem to be very mildly radioactive, so the fluorescence is likely caused by inclusions of a radioactive element like uranium.

The specimens we have are very small, little more than thumbnails or large chips.