Hydroxylherderite is a rare beryllium phosphate mineral typically found in granitic pegmatites. Collectors prize it for its excellent, often gemmy, orthorhombic-like monoclinic crystals and its characteristically strong yellow-green fluorescence under short-wave ultraviolet light.
Is this hydroxylherderite?
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 hydroxylherderite with a known reference. Hydroxylherderite sits at Mohs 5-5.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Hydroxylherderite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Hydroxylherderite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, white, yellow, green, violet.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic crystals, blocky crystals, sometimes massive.
Often confused with
Hydroxylherderite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside hydroxylherderite
Minerals reported to co-occur with hydroxylherderite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaBe(PO₄)(OH)
- Mohs hardness
- 5-5.5
- Density
- 2.95-3.05 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic Crystals, Blocky Crystals, Sometimes Massive
- Cleavage
- Poor in Two Directions
- Fluorescence
- Often Bright Yellow-green Under SW UV
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Granite Pegmatites
- Typical price
- $50-500 depending on crystal size and quality
Where rockhounds find hydroxylherderite
Classic worldwide localities
- Brazil
- USA (Maine)
- Pakistan
- Afghanistan
- Namibia
Field-hunting tip
Look in granite pegmatites country, the host setting where hydroxylherderite typically forms. If you start seeing albite, tourmaline, beryl in float, you are in the right ground. Field specimens usually show a prismatic crystals, blocky crystals, sometimes massive habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find hydroxylherderite on the map
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