Gypsum Crystal Cluster from Velké Němčice, Czech Republic

Large gypsum crystal cluster from Velké Němčice in the Czech Republic, featuring prominent, partly translucent tabular crystals intergrown with numerous smaller, thin-bladed crystals. The entire specimen exhibits yellowish-green fluorescence under UV light.

Fluorescent Gypsum Crystal Cluster from Velké Němčice

This gypsum specimen originates from Velké Němčice in the South Moravian Region of the Czech Republic. Measuring approximately 11 cm across, the specimen consists of numerous intergrown gypsum crystals of varying sizes. Several large, tabular crystals are particularly prominent, surrounded by smaller, thin-bladed crystals that form a distinctly three-dimensional cluster.

The crystals display predominantly light gray, beige, and slightly yellowish-brown tones. Some areas are translucent, and several larger crystals exhibit clearly developed faces and edges. Numerous smaller, thin tabular crystals occur in the center of the cluster, oriented in different directions. This irregular arrangement creates a varied crystalline structure that can be appreciated from several viewing angles.

A particularly interesting feature is the specimen’s yellowish-green fluorescence under UV light. The fluorescence extends throughout the entire crystal cluster. In the accompanying UV photograph, the response appears uneven because the UV lamp used was not powerful enough to illuminate the whole specimen uniformly. The excitation wavelength was not documented.

Under normal lighting, the specimen is equally interesting for its complex crystal arrangement. Larger, partly translucent gypsum crystals surround finer crystalline aggregates in the center. Some crystal surfaces show brownish discoloration and natural irregularities. With dimensions of 11 × 11 × 8 cm and a weight of 539 g, this is a substantial gypsum crystal cluster from a Czech mineral locality.