Senaite is a complex titanium-rich oxide member of the crichtonite group, often appearing as lustrous, opaque black rhombohedral crystals. It is most sought after by collectors for its occurrence in alpine-type fissures or specific igneous complexes. Careful examination of its crystal symmetry and associations helps distinguish it from more common iron-titanium oxides like ilmenite.
Is this senaite?
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 senaite with a known reference. Senaite sits at Mohs 6 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Senaite leaves a black streak.
- 3Read the lusterHold the specimen under a strong light. Senaite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: black.
- 5Look at form & habitCrystal system: trigonal. Typical habit: rhombohedral crystals, sometimes tabular.
Often confused with
Senaite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Luster reads metallic on Senaite and submetallic on Manaccanite.
How to tell apart: Streak differs — Senaite leaves black, Iron Ore leaves reddish-brown to black; luster reads metallic on Senaite and metallic to submetallic on Iron Ore.
Often found alongside senaite
Minerals reported to co-occur with senaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Pb(Ti,Fe,Mn,Zn)₂₁O₃₈
- Mohs hardness
- 6
- Density
- 5.3 g/cm³
- Colors
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Trigonal
- Crystal habit
- Rhombohedral Crystals, Sometimes Tabular
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Alpine Veins, Carbonatites, And Pegmatites
- Typical price
- $20-150 for thumbnail specimens
Where rockhounds find senaite
Classic worldwide localities
- Minas Gerais, Brazil
- St. Gotthard, Switzerland
- Kola Peninsula, Russia
- Magnet Cove, Arkansas, USA
Field-hunting tip
Look in alpine veins, carbonatites, and pegmatites country — that is the host setting where senaite typically forms. If you start seeing rutile, brookite, anatase in float, you are in the right ground. Field specimens usually show a rhombohedral crystals, sometimes tabular habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find senaite on the map
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