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 — that is 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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