Calcite from Iraí, Brazil – Scalenohedral Crystals with UV Fluorescence

This Calcite specimen from Iraí in Rio Grande do Sul, Brazil shows a three-dimensional group of white to cream-colored Calcite crystals on a greenish matrix. A distinctly larger, upright main crystal dominates the specimen and is accompanied by numerous smaller crystals that are predominantly scalenohedral in habit.

Measuring 5.4 × 4.5 × 4.0 cm and weighing 61.6 g including the acrylic base, this is a small cabinet specimen. The crystals are densely intergrown and form an attractive, fan-like crystal group.

Scalenohedral Calcite crystals with a dominant main crystal

The Calcite crystals are predominantly white to cream-colored and translucent. The main crystal shows locally brownish discoloration or coatings, especially in its upper area.

The crystal habit is predominantly scalenohedral, while the main crystal is distinctly elongated. The smaller crystals are densely arranged around it, creating a three-dimensional, radiating to fan-like appearance.

The luster is generally weak to moderate, although individual crystal faces reflect the light more strongly.

UV fluorescence under long-wave UV light

Under long-wave UV light, the Calcite shows clearly visible fluorescence. The fluorescent response adds another mineralogical feature to the specimen and makes it particularly interesting for collectors of fluorescent minerals.

The fluorescence is documented in a separate product image.

Calcite from Iraí, Brazil

The area around Iraí in the state of Rio Grande do Sul is known for mineral formation in basaltic rocks. Cavities and fractures within the volcanic rock provided space for the later crystallization of Calcite and other minerals.

This specimen shows the Calcite mineralization from Iraí in a particularly three-dimensional form. The combination of scalenohedral crystals, a dominant main crystal, greenish matrix and UV fluorescence makes the specimen both visually and mineralogically interesting.