Wolframite Identification Guide

What Wolframite Looks Like

Wolframite is an iron-manganese tungstate, (Fe,Mn)WO4, forming a series between ferberite (Fe-rich) and hübnerite (Mn-rich). It is the principal ore of tungsten. Color ranges from dark grayish-black to brownish-black (more reddish-brown in Mn-rich material). The luster is submetallic to resinous, and crystals are typically tabular or bladed with prominent lengthwise striations, often forming subparallel groups. It is opaque to translucent on thin edges.

Key Visual Cues

• Dark gray-black to brown-black color
• Submetallic to resinous luster
• Bladed/tabular striated crystals
• Surprisingly heavy in the hand (high density)

Step-by-Step Field ID Checklist

1. Heft it. Wolframite feels strikingly heavy (SG ~7.1–7.5) — a major clue.
2. Find the cleavage. One perfect cleavage produces flat, reflective surfaces in one direction.
3. Check the streak. A brown-black to reddish-brown streak is diagnostic.
4. Test hardness. Moderate (Mohs 4–4.5) — a knife scratches it, but a fingernail will not.
5. Look at the host. Wolframite typically sits in quartz veins or greisen near granite.

Diagnostic Tests

• Mohs hardness: 4–4.5 — scratched by a steel knife.
• Streak: Dark brown to reddish-brown to black.
• Cleavage/fracture: One perfect cleavage (pinacoidal); uneven fracture.
• Density: ~7.1–7.5 g/cm³ — very heavy.
• Magnetism: Generally weakly magnetic to non-magnetic (Fe-rich ferberite may show slight response, especially after heating).

Common Look-Alikes and How to Tell Them Apart

• Columbite-tantalite: Similar dark, dense, submetallic blades, but columbite has a different streak (dark red-brown to black) and association; chemistry/density tests separate them, and wolframite occurs in tungsten-tin veins.
• Hematite: Red-brown streak too, but hematite is harder (5–6) and often shows a more metallic or earthy habit; wolframite has perfect one-directional cleavage hematite lacks.
• Cassiterite (associated tin ore): Much harder (Mohs 6–7), adamantine luster, and a pale streak; often found with wolframite but easily separated by hardness.
• Ilmenite: Black, but lacks wolframite's perfect cleavage and bladed striated habit; ilmenite can be weakly magnetic.
• Manganite/other dark oxides: Lower density and different streak.

Where Wolframite Is Found

Wolframite occurs in high-temperature quartz veins, greisens, and pegmatites associated with granite intrusions, commonly with cassiterite, scheelite, arsenopyrite, and topaz. Major sources include China (the dominant producer), Portugal (Panasqueira), Bolivia, Myanmar, Russia, and historically Cornwall, England.

Collecting Tips

In the field, the combination of heavy heft, dark color, one perfect cleavage, and a brown-black streak strongly indicates wolframite. Search quartz veins and greisen near granite contacts, often alongside tin (cassiterite) mineralization. The streak test on unglazed porcelain is one of the quickest confirmations.