Spencerite is a rare secondary zinc phosphate mineral typically found in the oxidized zones of zinc-rich ore deposits. It often forms distinctive pearly, platy crystals or foliated masses associated with other zinc minerals like smithsonite.
Is this spencerite?
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 spencerite with a known reference. Spencerite sits at Mohs 2.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Spencerite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Spencerite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: white, colorless, gray.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: platy crystals, tabular aggregates.
Often confused with
Spencerite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Hopeite is the harder of the two (Mohs 3.5 vs. 2.5); luster reads pearly on Spencerite and vitreous on Hopeite.
How to tell apart: Parahopeite is the harder of the two (Mohs 3.5 vs. 2.5); luster reads pearly on Spencerite and vitreous on Parahopeite.
Often found alongside spencerite
Minerals reported to co-occur with spencerite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Zn₄(PO₄)₂(OH)₂·3H₂O
- Mohs hardness
- 2.5
- Density
- 3.1 g/cm³
- Streak
- White
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Platy Crystals, Tabular Aggregates
- Cleavage
- Perfect On {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Zinc Deposits
- Typical price
- $50-500 depending on specimen quality and size
Where rockhounds find spencerite
Classic worldwide localities
- Salmo, British Columbia, Canada
- Broken Hill, New South Wales, Australia
Field-hunting tip
Look in oxidized zinc deposits country, the host setting where spencerite typically forms. If you start seeing hopeite, smithsonite, hemimorphite in float, you are in the right ground. Field specimens usually show a platy crystals, tabular aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find spencerite on the map
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