3.6" Fluorapatite and Siderite Crystals on Arsenopyrite - Portugal

Fluorapatite and Siderite Crystals on Arsenopyrite - Portugal #239760

This is an eye-catching, 3.6" wide cluster of sage-green fluorapatite crystals that formed in association with siderite, all on a bed of intertwined arsenopyrite and ferberite crystals. It was collected from the Panasqueira Mines of Castelo Branco. This industrial mining center extends over 12.5 square miles and contains many mining sites, producing a wide variety of exceptional mineral specimens.

This specimen comes with an acrylic display stand.

Arsenopyrite is an iron arsenic sulfide with the chemical formula FeAsS. It is the most common arsenic-bearing mineral and is its principal ore, and can be found in igneous, metamorphic and sedimentary rock. Crystals can be found as prismatic, twinned, columnar, elongated and massive formations within veins and are found in locations all around the world. Depending on minerals present during formation, the iron in arsenopyrite can be replaced by cobalt, forming cobaltite.

Arsenopyrite contains a significant amount of poisonous arsenic, making it somewhat toxic. Washing hands following handling is recommended.

Fluorapatite is the most common variety in the apatite group. It forms early in almost all igneous rock as small, microscopic crystals. It can display a wide variety of colors and can be confused with beryl, phenakite and milarite. Often forming bright, lustrous crystals with hexagonal faces and off-center terminations. They are found in vugs, often associated with quartz and calcite. Most complete crystals are around an inch in length, though larger crystals up to about 4 inches long have been found.

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