Ushkovite is a rare phosphate mineral typically found as a secondary product in weathered granite pegmatites. Collectors look for its small, yellow, tabular triclinic crystals often occurring in intimate intergrowths with other phosphate species. It is most notable for its occurrence in complex phosphate-rich pegmatite environments where primary triphylite has undergone hydrothermal alteration.
Is this ushkovite?
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 ushkovite with a known reference. Ushkovite sits at Mohs 3.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: pale yellowish.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to pearly on cleavages, greasy on fractures.
- 4Match the color rangeCompare against the expected color range: brown, light yellow, orange.
- 5Look at form & habitCrystal system: triclinic. Typical habit: tabular crystals, radiating aggregates.
Often confused with
Ushkovite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Ushkovite leaves pale yellowish, Laueite leaves white.
How to tell apart: Streak differs, so Ushkovite leaves pale yellowish, Stewartite leaves white.
How to tell apart: Streak differs, so Ushkovite leaves pale yellowish, Pseudolaueite leaves white.
Often found alongside ushkovite
Minerals reported to co-occur with ushkovite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- MgFe³⁺₂(PO₄)₂(OH)₂·8H₂O
- Mohs hardness
- 3.5
- Density
- 2.38 g/cm³
- Colors
- Streak
- Pale yellowish
- Luster
- Vitreous to pearly on cleavages, greasy on fractures
- Transparency
- Transparent to translucent
- Crystal system
- Triclinic
- Crystal habit
- Tabular crystals, radiating aggregates
- Cleavage
- Perfect on {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In granite pegmatites, as an alteration product of triplite formed by weathering
Where rockhounds find ushkovite
Classic worldwide localities
- Palermo #1 mine, near North Groton, Grafton Co., New Hampshire, USA
- Dunton quarry, Newry, Oxford Co., Maine, USA
- Southern shore of Lake Bol’shoy Tatkul’, Il’men Mountains, Southern Ural Mountains, Russia
- Sandamap pegmatite, west of Usakos, Namibia
- Boa Vista, near Galiléia, Minas Gerais, Brazil
Field-hunting tip
Where it forms: In granite pegmatites, as an alteration product of triplite formed by weathering. If you start seeing triplite, francolite, mitridatite in float, you are in the right ground. Typical habit: tabular crystals, radiating aggregates. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify ushkovite?+
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What rocks look like ushkovite?+
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Find ushkovite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
