If the autunite (meta-autunite) specimens from this Portuguese mine are among the most aesthetic in the world due to their intense greenish-yellow colour, transparency and brilliance, they also stand out for being sometimes accompanied by another even more interesting species: phurcalite. It is also a hydrated calcium phosphate like autunite, but with a different structure and belonging to the phosphuranylite group (autunite is part of the autunite group).
In the analysis we have carried out by SEM-EDS (photo attached) the presence of the two phosphates becomes evident: the autunite as tabular crystals, while phurcalite appears as elongated prisms with defined terminal faces, which without magnification resemble needles. Apart from the appearance of the crystals, autunite usually has an intense greenish-yellow color and phurcalite is slightly orange-yellow. Also indicate that phurcalite does not usually fluoresce, while autunite is highly fluorescent. As we have indicated, sometimes the phurcalite is associated with autunite, so the fluorescence we see is that of the autunite. We will send analytical results to the buyer.

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