mineral
Small polished dark mineral specimen
Indeterminate; possibly black tourmaline (schorl) or hematite
AI-generated identification · may be incorrectA tiny black, polished, elongated specimen with submetallic to vitreous luster; details are insufficient for reliable hardness, cleavage, or specific-gravity determination. Schorl has Mohs hardness 7–7.5 and prismatic crystals; hematite has hardness 5–6.5 and a metallic-to-earthy luster.
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Physical properties
A tiny black, polished, elongated specimen with submetallic to vitreous luster; details are insufficient for reliable hardness, cleavage, or specific-gravity determination. Schorl has Mohs hardness 7–7.5 and prismatic crystals; hematite has hardness 5–6.5 and a metallic-to-earthy luster.
Formation & geological history
If schorl, it formed in granite pegmatites and hydrothermal veins; if hematite, it formed through oxidation or precipitation in sedimentary and hydrothermal environments. Geological ages vary widely.
Uses & applications
Used mainly as a collectible, carving, or jewelry bead; hematite is also an important iron ore, while tourmaline is valued as a gemstone.
Geological facts
A magnetism test, streak test, and close examination of crystal faces would help distinguish candidates. The image alone cannot confirm identity.
Field identification & locations
Common sources include Brazil, Africa, and the United States. Check whether it leaves a reddish-brown streak (hematite), shows prismatic striations and possible electric attraction when warmed (tourmaline), and avoid destructive testing on valuable pieces.
