Pyrite Penetration Twin from Navajún, Spain

This small Pyrite specimen from Navajún, Spain shows a striking intergrowth of two cubic crystals. The smaller crystal is strongly intergrown with the larger cube, forming a characteristic penetration twin with an almost cross-like geometry.

The metallic crystal faces show the typical appearance of Pyrite from Navajún. Despite its compact size of only 2.2 cm, the specimen has a distinctive three-dimensional form and is particularly interesting for collectors who appreciate well-defined cubic Pyrite crystals and unusual crystal intergrowths.

Cubic Pyrite crystals forming a penetration twin

The main crystal has a clearly cubic shape. A second Pyrite crystal is intensely intergrown with it and projects from the upper and front areas of the larger cube. Together, the two crystals form a pronounced penetration twin that appears different depending on the viewing angle.

The crystal faces display a strong metallic luster. Slight natural surface structures are visible on some faces. The combination of cubic crystal habit and the unusual intergrowth gives the specimen more visual interest than a simple isolated cube.

Pyrite from the classic Navajún locality

Navajún in the Spanish region of La Rioja is internationally known for exceptionally well-formed cubic Pyrite crystals. Specimens from this locality are especially appreciated for their clear geometric forms and pronounced metallic luster.

With dimensions of 2.2 × 2.2 × 2.0 cm and a weight of 36.6 g, this is a compact Thumbnail specimen. Its main appeal lies not in size, but in the distinctive penetration twin formed by the two intergrown crystals.