Light-colored crystals of hemimorphite on a red/brown limonitic gossan matrix, collected from the Ojuela Mine, Mapimí, Durango, Mexico. The hemimorphite fluoresces green under all UV wavelengths, brightest under mid wave UV. This specimen measures 8.4 x 8.0 x 5.1 cm and weighs 235 grams.
Full view images showing the specimen under mid wave UV and visible light.
The green fluorescence is no doubt caused by uranyl-activation- the presence of trace amounts of uranium in the hemimorphite, but this specimen does not emit detectable levels of radioactivity. The following images show close up detail of the hemimorphite crystals.
Macro images showing detail of the individual hemimorphite crystals under mid wave UV (left) and visible light (right). Horizontal field of view is 32 mm. Click on image for a larger view.