Petersite-(Y) is a rare yttrium-dominant member of the mixite group that typically forms striking, delicate fibrous tufts or spherical aggregates. Collectors look for its characteristic mustard-yellow to greenish-yellow color, often occurring on or within quartz vugs.
Is this petersite-(y)?
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 petersite-(y) with a known reference. Petersite-(Y) sits at Mohs 3-4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Petersite-(Y) leaves a pale yellow streak.
- 3Read the lusterHold the specimen under a strong light. Petersite-(Y) typically shows a silky luster.
- 4Match the color rangeCompare against the expected color range: yellow, brown, greenish-yellow.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: fibrous aggregates, sprays, tufts.
Often confused with
Petersite-(Y) vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside petersite-(y)
Minerals reported to co-occur with petersite-(y). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Y,Ce,Nd,Ca)Cu₆(PO₄)₃(OH)₆·3H₂O
- Mohs hardness
- 3-4
- Density
- 4.15 g/cm³
- Streak
- Pale Yellow
- Luster
- Silky
- Transparency
- Translucent
- Crystal system
- Hexagonal
- Crystal habit
- Fibrous Aggregates, Sprays, Tufts
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Veins in Metamorphic Rocks
- Typical price
- $50-500 depending on specimen quality and size
Where rockhounds find petersite-(y)
Classic worldwide localities
- Xitieshan mine, China
- Arizona, USA
- Czech Republic
Field-hunting tip
Look in hydrothermal veins in metamorphic rocks country — that is the host setting where petersite-(y) typically forms. If you start seeing quartz, goethite, chalcopyrite in float, you are in the right ground. Field specimens usually show a fibrous aggregates, sprays, tufts habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify petersite-(y)?+
Where is petersite-(y) found?+
How much is petersite-(y) worth?+
Is petersite-(y) safe to handle?+
What rocks look like petersite-(y)?+
What minerals are found with petersite-(y)?+
What kind of rock does petersite-(y) form in?+
What is petersite-(y) used for?+
Find petersite-(y) on the map
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