Foordite is a rare tin-niobium oxide belonging to the tapiolite group. It is primarily found in granitic pegmatite environments and is visually difficult to distinguish from other dark, opaque oxide minerals without chemical analysis. Collectors typically seek it for its rarity and its specific association with pegmatite mineral suites.
Is this foordite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch foordite with a known reference. Foordite sits at Mohs 6-6.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Foordite leaves a black streak.
- 3Read the lusterHold the specimen under a strong light. Foordite typically shows a submetallic luster.
- 4Match the color rangeCompare against the expected color range: black, brownish-black.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: prismatic to tabular crystals.
Often confused with
Foordite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Foordite leaves black, Columbium Ore leaves dark red to black.
How to tell apart: Streak differs — Foordite leaves black, Cassiterite leaves white; luster reads submetallic on Foordite and adamantine on Cassiterite.
Often found alongside foordite
Minerals reported to co-occur with foordite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Sn,Fe)Nb₂O₆
- Mohs hardness
- 6-6.5
- Density
- 7.3 g/cm³
- Colors
- Streak
- Black
- Luster
- Submetallic
- Transparency
- Opaque
- Crystal system
- Tetragonal
- Crystal habit
- Prismatic to Tabular Crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector, Scientific Research
- Host rock
- Granite Pegmatites
- Typical price
- $50-300 per specimen
Where rockhounds find foordite
Classic worldwide localities
- Antsongombato, Madagascar
Field-hunting tip
Look in granite pegmatites country — that is the host setting where foordite typically forms. If you start seeing quartz, albite, muscovite in float, you are in the right ground. Field specimens usually show a prismatic to tabular crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find foordite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
