Calcite with Apophyllite from Jalgaon, India

This mineral specimen comes from the Jalgaon district in Maharashtra, India. Two prominent pale calcite crystals rise from a dark volcanic matrix and are accompanied by numerous colorless to white apophyllite crystals.

The calcite forms broad, clearly defined rhombohedral crystals. The larger crystal at the front is partly transparent to translucent and shows visible internal structures, while the second crystal has a pale cream to grayish-white coloration and appears more translucent to opaque. Their surfaces show a moderate vitreous luster.

Numerous smaller apophyllite crystals cover the upper and lateral areas of the specimen. They form colorless to white, transparent to translucent crystals with square to rectangular outlines and bright reflective faces. The contrast between the large calcite crystals, the smaller apophyllite group, and the dark matrix gives the specimen a distinctly three-dimensional appearance.

Measuring 8.5 × 5.0 × 3.5 cm, the piece belongs to the cabinet specimen size category. It weighs 139.4 g.

Calcite and Apophyllite from the Deccan Traps

The Jalgaon district is part of the Deccan Traps, an extensive sequence of basaltic lava flows in western India. Gas cavities and fractures remained within the volcanic rock as the lava cooled.

Mineral-bearing fluids later circulated through these open spaces. Calcite and minerals of the apophyllite group crystallized on the cavity walls, frequently together with zeolites and other secondary minerals.

The association of large rhombohedral calcite crystals with smaller apophyllite crystals on dark volcanic matrix is characteristic of the mineralization found in Maharashtra.