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, so 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, 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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