Rock Crystal on Calcite from Igea, La Rioja – Self-Collected Specimen

This rock crystal specimen from Igea in La Rioja, Spain features an approximately 1.2 cm long, clear quartz crystal resting on a surface densely covered with calcite. The rock crystal stands out clearly from the cream-colored to whitish calcite crystals because of its transparency and forms the visual focal point of the specimen.

With dimensions of 8.9 × 4.5 × 1.5 cm and a weight of 101.4 g, this is a relatively large matrix specimen. I collected the piece myself in Igea. The back of the plate has been sawn, creating a flat surface that allows the specimen to be displayed securely.

Doubly terminated rock crystal on calcite

The approximately 1.2 cm long rock crystal shows a doubly terminated habit and sits freely on the mineralized surface. Its clear to slightly included appearance distinguishes it well from the lighter surrounding matrix.

The associated calcite crystals are predominantly lenticular to bladed and cover large areas of the surface. Their cream-white to slightly yellowish coloration provides a subdued background for the colorless quartz crystal.

The contrast in crystal morphology is particularly interesting: while the quartz is compact and clearly bounded, the calcite forms a dense surface coating made up of numerous lenticular crystals.

Self-collected specimen from Igea in La Rioja

Igea in La Rioja is known for various quartz and calcite mineralizations. This specimen clearly illustrates the association of rock crystal and calcite on sedimentary matrix.

The appeal of the piece lies less in the size of the quartz crystal than in its doubly terminated development, its isolated position on the calcite-covered surface, and the contrast between transparent quartz and cream-colored calcite. The sawn back also reflects the preparation of the plate for stable display.