Pyrite Crystals on Matrix from Ambas Aguas, Spain

This pyrite specimen comes from Ambas Aguas in the Spanish province of La Rioja. Several brass-yellow to golden-yellow pyrite crystals sit freely on a natural rock matrix.

The largest crystal reaches approximately 2.5 cm in diameter and shows a complex, possibly twinned development. In addition to cubic faces, pyritohedral faces are also visible. Further smaller pyrite crystals are distributed three-dimensionally across the matrix.

Depending on the lighting, the crystal faces show a distinct metallic luster. Some faces reflect the light strongly, while others appear more subdued because of natural surface textures.

Measuring 12.0 × 8.0 × 8.0 cm, the piece belongs to the large cabinet specimen size category. It weighs 785 g.

Multi-Faced Pyrite from Ambas Aguas

Ambas Aguas is one of the well-known Spanish localities for pyrite. In contrast to the frequently cubic pyrite crystals from Navajún, specimens from Ambas Aguas may also show multi-faced crystals with clearly developed pyritohedral faces.

The pyrite crystals formed within sedimentary rocks and were partly exposed together with their natural matrix during extraction. Larger intact matrix specimens are more difficult to recover and transport than individual loose crystals.

The large main crystal, the variety of crystal faces, and the spatial distribution of the pyrite crystals make this piece a characteristic locality specimen from Ambas Aguas.