Piemontite-(Sr) is a rare member of the epidote group characterized by significant strontium substitution. It typically presents as striking reddish-brown prismatic crystals or fibrous aggregates, often found in manganese-enriched metamorphic environments.
Is this piemontite-(sr)?
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 piemontite-(sr) with a known reference. Piemontite-(Sr) sits at Mohs 6-7 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Piemontite-(Sr) leaves a reddish-brown streak.
- 3Read the lusterHold the specimen under a strong light. Piemontite-(Sr) typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: red, reddish-brown, dark red.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic crystals, radial aggregates, massive.
Often confused with
Piemontite-(Sr) vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Piemontite-(Sr) leaves reddish-brown, Epidote leaves white.
How to tell apart: Streak differs — Piemontite-(Sr) leaves reddish-brown, Allanite leaves gray; luster reads vitreous on Piemontite-(Sr) and submetallic on Allanite.
Often found alongside piemontite-(sr)
Minerals reported to co-occur with piemontite-(sr). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaSrAl₂Mn³⁺(SiO₄)(Si₂O₇)O(OH)
- Mohs hardness
- 6-7
- Density
- 3.5-3.6 g/cm³
- Colors
- Streak
- Reddish-brown
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic Crystals, Radial Aggregates, Massive
- Cleavage
- Perfect On {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Manganese-rich Metamorphic Rocks, Skarns
- Typical price
- $20-150 thumbnail, $200+ cabinet specimen
Where rockhounds find piemontite-(sr)
Classic worldwide localities
- Saint-Marcel, Italy
- Jacupiranga, Brazil
- Japan
Field-hunting tip
Look in manganese-rich metamorphic rocks, skarns country — that is the host setting where piemontite-(sr) typically forms. If you start seeing quartz, calcite, manganese minerals in float, you are in the right ground. Field specimens usually show a prismatic crystals, radial aggregates, massive habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify piemontite-(sr)?+
Where is piemontite-(sr) found?+
How much is piemontite-(sr) worth?+
What rocks look like piemontite-(sr)?+
What minerals are found with piemontite-(sr)?+
What kind of rock does piemontite-(sr) form in?+
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Find piemontite-(sr) on the map
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