Hedyphane is a rare lead-calcium arsenate member of the apatite group often found in metamorphosed ore deposits. Collectors identify it by its resinous luster and distinct bright yellow fluorescence under short-wave ultraviolet light.
Is this hedyphane?
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 hedyphane with a known reference. Hedyphane sits at Mohs 4.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to greasy.
- 4Match the color rangeCompare against the expected color range: white, blue, gray white, yellowish white.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: crystalline, massive.
Often confused with
Hedyphane vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads vitreous to greasy on Hedyphane and resinous to subadamantine on Mimetite.
How to tell apart: Hedyphane is noticeably harder (Mohs 4.5 vs. 2.5-3); luster reads vitreous to greasy on Hedyphane and subresinous to subadamantine on Vanadinite.
Often found alongside hedyphane
Minerals reported to co-occur with hedyphane. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Ca,Pb)₅(AsO₄)₃Cl
- Mohs hardness
- 4.5
- Density
- 5.71-5.85 g/cm³
- Streak
- White
- Luster
- Vitreous to greasy
- Transparency
- Translucent
- Crystal system
- Hexagonal
- Crystal habit
- Crystalline, massive
- Cleavage
- On {1011}, poor
- Fluorescence
- Light yellow under SW and LW UV
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A rare secondary mineral in metamorphosed manganese deposits (Sweden); in a metamorphosed stratiform zinc orebody (Franklin, New Jersey, USA)
Where rockhounds find hedyphane
Classic worldwide localities
- Franklin, Sussex Co., New Jersey, and the Balmat #4 mine, Fowler, St. Lawrence Co., New York, USA
- Långban, Nordmark, and the Harstigen mine, near Persberg, Värmland, and the Sjö mine, near Grythyttan, Örebro, Sweden
- Brandy Gill, Caldbeck Fells, Cumbria, England
- Tynagh mine, near Loughrea, Co. Galway, Ireland
- San Carlos mine, Santa Eulalia, Chihuahua, Mexico
- Tsumeb, Namibia
Field-hunting tip
Where it forms: A rare secondary mineral in metamorphosed manganese deposits (Sweden); in a metamorphosed stratiform zinc orebody (Franklin, New Jersey, USA). If you start seeing barite, barylite, rhodonite in float, you are in the right ground. Typical habit: crystalline, massive. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify hedyphane?+
Where is hedyphane found?+
Is hedyphane safe to handle?+
What rocks look like hedyphane?+
What minerals are found with hedyphane?+
What kind of rock does hedyphane form in?+
What is hedyphane used for?+
Find hedyphane on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
