Priderite is a rare titanium-rich member of the hollandite group typically found in potassic igneous rocks like lamproites. Collectors should look for its distinctive prismatic black crystals embedded in volcanic or intrusive matrices. It is primarily valued by mineralogists for its complex crystal structure and unique occurrence in specific alkaline environments.
Is this priderite?
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 priderite with a known reference. Priderite sits at Mohs 7, 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: adamantine.
- 4Match the color rangeCompare against the expected color range: black, reddish, reddish black.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: prismatic, tabular.
Often confused with
Priderite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Priderite is noticeably harder (Mohs 7 vs. 6); streak differs, so Priderite leaves gray, Hollandite leaves black; luster reads adamantine on Priderite and metallic, splendent on Hollandite.
How to tell apart: Streak differs, so Priderite leaves gray, Cryptomelane leaves brownish black; luster reads adamantine on Priderite and metallic to dull on Cryptomelane.
Often found alongside priderite
Minerals reported to co-occur with priderite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- K(Ti₇Fe)O₁₆
- Mohs hardness
- 7
- Density
- 3.86 g/cm³
- Streak
- Gray
- Luster
- Adamantine
- Transparency
- Semitransparent
- Crystal system
- Tetragonal
- Crystal habit
- Prismatic, tabular
- Cleavage
- {001}, perfect; another, perpendicular, fair
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In some ultrapotassic lamproites, ultramafics, and carbonatites
Where rockhounds find priderite
Classic worldwide localities
- Leucite Hills, Sweetwater Co., Wyoming, USA
- Smoky Butte, Garfield Co., Montana, USA
- Prairie Creek diatreme, near Murfreesboro, Pike Co., Arkansas, USA
- Kimberley district, Western Australia, as in the Wolgidee Hills and the Argyle diamond mine
- Island of Corsica, France, near Sisco, north of Bastia
- Sisimiut area, west Greenland
Field-hunting tip
Where it forms: In some ultrapotassic lamproites, ultramafics, and carbonatites. If you start seeing leucite, potassian richterite, titanian phlogopite in float, you are in the right ground. Typical habit: prismatic, tabular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify priderite?+
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What rocks look like priderite?+
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Find priderite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
