Calcite and sphalerite elmwood USA

Specimen description

This specimen combines sphalerite with large translucent calcite crystals, displaying tones ranging from pale yellow to honey yellow. Calcite accounts for most of the specimen's volume, with thick crystals showing broad faces and angular forms that can be observed clearly from different angles.

Several crystals and small groups of very dark brown to nearly black sphalerite occur on different areas of the calcite. Their dark color and distinct luster stand out against the lighter calcite crystals.

With its dimensions and a weight of more than one kilogram, this is a substantial specimen. The video shows the distribution of sphalerite around the calcite crystals, as well as the translucency and variations in color of the calcite depending on the crystal faces and viewing angle.

Calcite and sphalerite

Calcite is a calcium carbonate with the chemical formula CaCO₃. Sphalerite is a zinc sulfide with the formula ZnS, in which iron can substitute for zinc in variable proportions.

Provenance

This specimen comes from the Elmwood Mine near Carthage, Smith County, Tennessee, USA. This mining locality is well known for its calcite, sphalerite and fluorite crystals, as well as other minerals including baryte, dolomite and galena. The specimen was collected in 1998.

Dimensions and presentation

Stone dimensions: 150 × 90 × 100 mm.

Weight: 1,070 g.