Cassiterite (Stream Tin)- South Dakota, USA

Cassiterite (Stream Tin)
South Dakota, USA
Dimensions: 1.5 × 4.9 cm (glass vial)
Provenance: Original vintage collection label, catalog no. 136, included with specimen.

A vintage collection of stream tin consisting of numerous small, dark brown to nearly black mineral grains preserved in a cork-stoppered glass vial. The granular material displays a mixture of glossy black, bronze-brown, and golden-brown particles, with individual grains catching the light to produce a subtle metallic-looking sparkle. The contrasting colors and varied grain sizes create an interesting example of naturally concentrated heavy-mineral sediment.

Cassiterite is a tin oxide mineral (SnO₂) and the principal ore of tin. The term stream tin refers to cassiterite grains that have been weathered from their original deposits, transported by water, and concentrated in stream sediments due to their relatively high density. South Dakota's Black Hills region has a documented history of tin mineralization associated with granitic pegmatites, making stream tin an interesting part of the state's mining and mineralogical heritage. This vintage-labeled vial offers a collectible example of historic placer-style mineral material.