Strontiopharmacosiderite is a rare member of the pharmacosiderite group, characterized by its distinct cubic habit and yellowish hues. It is a secondary mineral typically found in the gossan zones of arsenic-rich hydrothermal deposits, often occurring as small pseudocubic crystals. Due to its arsenic content, collectors should exercise caution during handling and storage.
Is this strontiopharmacosiderite?
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 strontiopharmacosiderite with a known reference. Strontiopharmacosiderite 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. Strontiopharmacosiderite leaves a yellow streak.
- 3Read the lusterHold the specimen under a strong light. Strontiopharmacosiderite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, greenish-yellow, yellowish-brown.
- 5Look at form & habitCrystal system: cubic. Typical habit: pseudocubic crystals, granular aggregates.
Often confused with
Strontiopharmacosiderite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Strontiopharmacosiderite leaves yellow, Pharmacosiderite leaves white; luster reads vitreous on Strontiopharmacosiderite and adamantine on Pharmacosiderite.
How to tell apart: Scorodite is the harder of the two (Mohs 3.5-4 vs. 2.5); streak differs — Strontiopharmacosiderite leaves yellow, Scorodite leaves white; luster reads vitreous on Strontiopharmacosiderite and vitreous to sub-adamantine on Scorodite.
Often found alongside strontiopharmacosiderite
Minerals reported to co-occur with strontiopharmacosiderite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- SrFe₄(AsO₄)₃(OH)₅·5H₂O
- Mohs hardness
- 2.5
- Density
- 2.88 g/cm³
- Streak
- Yellow
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Cubic
- Crystal habit
- Pseudocubic Crystals, Granular Aggregates
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Zones of Arsenic-rich Hydrothermal Mineral Deposits
- Typical price
- $50-300 per specimen
Where rockhounds find strontiopharmacosiderite
Classic worldwide localities
- Kurnakovsky deposit, Russia
- San Telmo mine, Spain
- Wheal Gorland, United Kingdom
Field-hunting tip
Look in oxidized zones of arsenic-rich hydrothermal mineral deposits country — that is the host setting where strontiopharmacosiderite typically forms. If you start seeing arsenopyrite, goethite, limonite in float, you are in the right ground. Field specimens usually show a pseudocubic crystals, granular aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify strontiopharmacosiderite?+
Where is strontiopharmacosiderite found?+
How much is strontiopharmacosiderite worth?+
Is strontiopharmacosiderite safe to handle?+
What rocks look like strontiopharmacosiderite?+
What minerals are found with strontiopharmacosiderite?+
What kind of rock does strontiopharmacosiderite form in?+
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Find strontiopharmacosiderite on the map
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