Gesso var. Selenite Crystals on matrix - Height: 19 cm - Width: 16 cm- 2.42 kg - (1)

Important specimen of Gypsum (selenite variety) from the historic Niccioleta Mine, in the Massa Marittima area, Grosseto province. The locality is known mainly for pyrite and for the remarkable gypsum crystals, often found in association with metallic sulfides.

The specimen consists of a rich aggregate of translucent gypsum crystals, some of which reach considerable sizes. The crystals display elongated and flattened shapes, with surfaces marked by evident growth striations. The crisscross arrangement of the numerous elements creates a complex, developed, and very dramatic structure.

Notably standing out is the large vertical crystal placed on one side of the specimen, flanked by several smaller crystals oriented in various directions. The transparency ranges from nearly clear to milky, while inclusions and the slight coloration due to the matrix make each crystal unique.

Among the gypsum crystals there are gray-bronze metallic aggregates attributable to pyrite, a characteristic mineral of the Niccioleta Mine and documented in association with gypsum from the locality. The matrix also shows brown, reddish, and ochre tones due to natural encrustations and alteration products.

With a weight over 2.4 kg and dimensions close to 20 cm, this is a specimen of notable presence, suitable for a significant collection of Italian minerals and particularly representative of the historic mineralogy of the Metalliferous Hills.

Gypsum is a naturally soft and easily split mineral. As visible in the photographs, some crystals show contacts, cleavage, and small imperfections compatible with the nature of the mineral.

Provenance: Niccioleta Mine, Massa Marittima, Grosseto, Tuscany, Italy
Weight: 2.423 kg
Dimensions: 19 × 16 × 12 cm

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