Autunite, Uranophane on Albite

Specimen Origin: Ruggles Mine (Grafton County, New Hampshire, USA)

The Ruggles Mine, located on Isinglass Mountain in Grafton County, New Hampshire, is a historic pegmatite worked for over a century for mica, feldspar, and beryl. Within its complex pegmatite zones, secondary uranium minerals such as autunite and uranophane formed in fractures and cavities, often as delicate coatings on albite crystals. These associations create visually striking specimens, where the vivid yellow-green fluorescence of uranium minerals contrasts sharply against the white to translucent feldspar matrix.

Autunite, Uranophane on Albite

Autunite is a hydrated calcium uranyl phosphate with bright yellow-green tabular crystals, while uranophane is a hydrated calcium uranium silicate that appears as fibrous, canary-yellow sprays. Both are strongly radioactive and fluorescent under ultraviolet light. Their occurrence on albite, a sodium-rich feldspar, highlights the secondary alteration processes in pegmatitic environments and makes these specimens desirable for both their aesthetic qualities and mineralogical significance.