Sphalerite

This specimen is interpreted as sphalerite, the principal ore of zinc, occurring here as a massive, dark brown to black aggregate. The surface shows a dull to sub-metallic lustre with areas of rusty brown and ochre weathering, consistent with iron-rich sphalerite that has undergone surface oxidation. Fresh sphalerite typically displays resinous to adamantine lustre and may show brown, honey, or black coloration depending on iron content. In weathered specimens such as this, original crystal faces are often obscured, leaving a compact, granular to massive texture. The appearance, colour, and texture closely match documented sphalerite specimens from Johnston(s) United Mine in the Lyall Collection, supporting the label attribution.