Lueshite is a rare niobium-bearing mineral typically found as small, black, pseudo-cubic crystals in alkaline igneous complexes. Collectors often search for it in syenitic pegmatites or carbonatites where it occurs alongside other exotic silicate and oxide minerals.
Is this lueshite?
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 lueshite with a known reference. Lueshite sits at Mohs 5-5.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: gray.
- 3Read the lusterHold the specimen under a strong light. Luster: submetallic.
- 4Match the color rangeCompare against the expected color range: black, brown.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: cubic to pseudo-cubic crystals, sometimes elongated or flattened.
Often confused with
Lueshite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Lueshite leaves gray, Perovskite leaves white to grayish white; luster reads submetallic on Lueshite and adamantine to metallic; may be dull on Perovskite.
How to tell apart: Streak differs, so Lueshite leaves gray, Pyrochlore leaves brown; luster reads submetallic on Lueshite and vitreous to resinous on Pyrochlore.
How to tell apart: Streak differs, so Lueshite leaves gray, Loparite leaves brown; luster reads submetallic on Lueshite and metallic on Loparite.
Often found alongside lueshite
Minerals reported to co-occur with lueshite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NaNbO₃
- Mohs hardness
- 5-5.5
- Density
- 4.44 g/cm³
- Streak
- Gray
- Luster
- Submetallic
- Transparency
- Opaque, translucent on thin edges
- Crystal system
- Orthorhombic
- Crystal habit
- Cubic to pseudo-cubic crystals, sometimes elongated or flattened
- Cleavage
- {001}, imperfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Incrusting a vermiculitelike mica, at the contact of cancrinite syenite with carbonatite (Lueshe, Congo); in sodalite xenoliths associated with an intrusive alkalic gabbro-syenite complex (Mont Saint-Hilaire, Canada)
Where rockhounds find lueshite
Classic worldwide localities
- Gem Park, about six km east of Hillside, Fremont Co., Colorado, USA
- Lueshe carbonatite, 150 km north of Goma, Kivu Province, Congo (Zaire)
- Mont Saint-Hilaire and near Saint-Amable, Quebec, Canada
- Igdlunguaq, in the Ilímaussaq intrusion, Greenland
- Kovdor, Sallanlatvi, Lesnaya Varaka, and Lovozero massifs, Kola Peninsula, and unidentified carbonatites in Siberia, Russia
Field-hunting tip
Where it forms: Incrusting a vermiculitelike mica, at the contact of cancrinite syenite with carbonatite (Lueshe, Congo); in sodalite xenoliths associated with an intrusive alkalic gabbro-syenite complex (Mont Saint-Hilaire, Canada). If you start seeing mica, sodalite, ussingite in float, you are in the right ground. Typical habit: cubic to pseudo-cubic crystals, sometimes elongated or flattened. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify lueshite?+
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What rocks look like lueshite?+
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Find lueshite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
