Tharsis Mines, Tharsis, Alosno, Huelva, Andalusia, Spain

Dimensions (H x W x D)

.5 x 11.5 x 3.5 cm


270 g

Description & Provenance

The Andalusia region of Spain is famous for its vibrant heritage and abundant natural resources. Beneath its rich soil lies the Iberian Pyrite Belt, which contains the largest massive sulfide concentration in the world. The area has been mined for thousands of years and has been known to produce vast amounts of ore and some excellent specimens too. The mines of Tharsis, in particular, have produced excellent botryoidal (grapelike) and/or stalactitic goethite specimens with eye-catching, multicolored exteriors that are unlike the more typical, gunmetal tone associated with the species. Most exhibit a metallic version of the different colors, as though an artist blended pigments with silver paint. This iridescent display is sometimes referred to as “turgite.” Despite its name, it is not a mineral in and of itself, it’s a mix of two minerals after the alternation of goethite. It consists of either hematite or goethite. Color combinations are varied and may be blue and pink, yellow and blue, orange and green, or even a full spectrum of tones on a single specimen. The visual effect is similar to that of the rainbows in an oil spill but captured in “stone.”

This is a fantastic example of Tharsisian goethite that is composed of a network of distinctive, branch-like structures that are intertwined with one another. Small botryoidal forms can be seen throughout, underneath, on top of, and a part of the branches. The effect of the composition is similar to seeing a crisscross of veins or a network of roots, all leading to different directions. The overall specimen has a peaked form and a likeness to a shark’s fin in shape. Its most striking feature, however, is its stunningly vivid array of colors. Their hues are more intense and far richer than the vast majority of specimens which are more silver-toned and subdued. This vibrant specimen was recovered by a group of enthusiastic mineral collectors who saw an opportunity for minerals by the roadside. It was found in 1987 along the road between the two small towns of Tharsis and Alosno (with not eight kilometers between them).

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