Danburite Identification Guide
Identify Danburite by its colorless-to-pale prismatic crystals, chisel-like terminations, hardness 7-7.5, and weak fluorescence.
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What Danburite Looks Like
Danburite (a calcium borosilicate) forms transparent to translucent prismatic crystals that are usually colorless, but also occur pale pink, yellow, or champagne. Crystals are typically elongated prisms with lengthwise striations and a distinctive wedge- or chisel-shaped (roof-like) termination. The luster is vitreous to slightly greasy, and the stone superficially resembles colorless topaz or quartz.
- Color: colorless, white, pale yellow, pink, or brownish
- Luster: vitreous to greasy
- Transparency: transparent to translucent
- Habit: elongated, striated prisms with chisel-like (wedge) terminations
Step-by-Step Field-ID Checklist
- Note crystal shape. Elongated, vertically striated prisms ending in a flattened chisel-like point are characteristic.
- Hardness test. Danburite scratches glass and just scratches quartz (Mohs ~7-7.5).
- Check cleavage. Danburite has poor/indistinct cleavage and breaks with a conchoidal-to-uneven fracture (helps separate from topaz).
- Try UV light. Many danburites fluoresce sky-blue to blue-green under UV (especially long-wave) and may phosphoresce.
- Assess weight. Density ~3.0, slightly heavier than quartz but lighter than topaz.
Key Diagnostic Tests
- Mohs hardness: 7-7.5; scratches glass and quartz.
- Streak: white.
- Cleavage: poor/indistinct (unlike topaz's perfect basal cleavage).
- Fluorescence: commonly sky-blue to blue-green under UV; some phosphoresce.
- Density: ~2.97-3.02 g/cm3.
Common Look-Alikes and How to Tell Them Apart
- Topaz: Similar colorless gem and hardness, but topaz has perfect basal cleavage (one flat break direction) and higher density (~3.5); danburite has poor cleavage and is lighter, and topaz crystals are differently terminated.
- Quartz: Softer (Mohs 7 vs 7-7.5), with horizontal striations on hexagonal prisms and no fluorescence; danburite has vertical striations and chisel terminations and often fluoresces.
- Beryl (goshenite): Hexagonal prisms with flat ends; danburite is orthorhombic with wedge terminations and is lighter (beryl ~2.7).
- Phenakite/apatite: Apatite is much softer (Mohs 5); phenakite is harder and rarer with different habit.
- Glass: No crystal striations, often has bubbles, and is softer; danburite shows true crystal faces.
Where It Is Found
Danburite is named for Danbury, Connecticut, USA. The finest gem crystals come from Charcas and other localities in Mexico, plus Myanmar, Madagascar, Japan, Russia, and Tanzania.
Frequently asked questions
How can you tell if it's real Danburite?
Real danburite forms colorless-to-pale prismatic crystals with vertical striations and a chisel-like termination, has a hardness of 7-7.5 (scratches glass and quartz), shows poor cleavage with conchoidal fracture, and often fluoresces sky-blue under UV light.
What does Danburite look like?
It looks like a clear-to-translucent gem, often colorless (also pink, yellow, or champagne), in elongated striated prisms ending in a flattened wedge or chisel-shaped point, with a glassy luster.
Danburite vs topaz: what's the difference?
Both are hard and can be colorless, but topaz has perfect basal cleavage and a higher density (~3.5), while danburite has poor cleavage and a lighter density (~3.0) and frequently fluoresces blue under UV.
Danburite vs quartz: how do I tell them apart?
Danburite is slightly harder (7-7.5), has vertical striations and chisel terminations, and often fluoresces, whereas quartz is Mohs 7 with horizontal striations on hexagonal prisms and does not fluoresce.
Does Danburite glow under UV light?
Often, yes. Many danburite crystals fluoresce sky-blue to blue-green under ultraviolet light, particularly long-wave UV, and some even phosphoresce briefly afterward.