Corkite crystals from Cercal do Alentejo, Santiago do Cacém, Setúbal, Portugal, Gerd Tremmel collection – small cabinet specimen as unique piece
This small cabinet specimen with Corkite crystals from Cercal do Alentejo, Santiago do Cacém, Setúbal, Portugal, originates from the Gerd Tremmel collection and represents a particularly high contrast and aesthetic example of this rare phosphate mineral. The Corkite crystals occur as numerous fine yellow to golden crystals densely covering a deep dark brown to nearly black matrix.
The crystals form dense, evenly distributed coatings and appear as fine crystalline, clearly recognizable crystal carpets with a sparkling surface. The dark, partly lustrous and irregularly structured matrix strongly enhances the visual contrast and highlights the bright Corkite crystals. This results in an exceptionally decorative appearance with strong visual depth.
Geology & Origin
Cercal do Alentejo in the Santiago do Cacém area, Setúbal region, is known for secondary phosphate mineralization formed through weathering and oxidation processes. Corkite belongs to the alunite group and forms under oxidizing conditions in iron rich deposits. The fine, densely packed crystals typically develop as coatings on the matrix and are characteristic of this geochemical environment.