Specular Hematite and Magnetite Ore

Physical Properties

Hardness: 5.5-6.5 (Mohs scale); Color: Steel grey to black with metallic silver glitter; Luster: Sub-metallic to metallic; Crystal Structure: Rhombohedral; Specific Gravity: 5.2-5.3; Streak: Cherry red to reddish-brown.

Formation & Geological History

Formed primarily in banded iron formations (BIFs) through chemical precipitation in ancient oceans or via hydrothermal replacement and metamorphism of iron-rich sediments, typically dating from the Proterozoic eon.

Uses & Applications

Primary source of iron for steel manufacturing; also used for heavy media separation, pigments, and balance weights. High-grade specularite is often sought after for mineral specimen collections.

Geological Facts

Specularite gets its name from 'speculum' (Latin for mirror) because it was once used as a reflective surface. It is often mildly magnetic if it contains trace amounts of magnetite, which is common in massive iron ore samples like this.

Field Identification & Locations

Identify in the field by its high density (feels heavy for its size) and by doing a streak test on unglazed porcelain—hematite will leave a distinctive red/brown streak regardless of its dark grey surface color.

Identified on: 4/22/2026

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