Danburite
Calcium borosilicate (CaB2Si2O8)
A glassy calcium borosilicate forming wedge-tipped prismatic crystals, usually colorless to pale yellow or pink, sometimes faceted as a gem.
- Mohs hardness
- 7-7.5
- Color
- Colorless, white, pale yellow, pink, lilac
- Type
- crystal
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Overview
Danburite is a calcium borosilicate mineral that forms transparent, glassy prismatic crystals, typically colorless or white but also pale yellow, pink, or lilac. It was first described in 1839 from Danbury, Connecticut, which gives it its name.
Its crystals are orthorhombic, often with a distinctive chisel- or wedge-shaped termination, and superficially resemble topaz or quartz. Danburite has a high hardness and bright vitreous luster, making the clearer material attractive when faceted.
Though not widely known to the general public, it is popular among mineral collectors and in the metaphysical market. Fine crystals come from Mexico, Myanmar, Japan, Madagascar, and the original Connecticut locality.
Formation & geology
Danburite forms in contact metamorphic and hydrothermal environments, especially where boron-bearing fluids interact with calcium-rich rocks such as limestone or dolomite. It is commonly found in skarns, evaporite-related deposits, and in cavities and veins associated with metamorphosed carbonate rocks.
It also occurs in some granite-related and pegmatitic settings. Well-formed crystals grow in vugs where there was space for free growth. Notable localities include Charcas in San Luis Potosi, Mexico (famous for large clear crystals), Myanmar, Japan, Madagascar, Russia, and Danbury, Connecticut, USA, the type locality.
How to identify it
Look for transparent, glassy, elongated prismatic crystals with lengthwise striations and a wedge- or chisel-shaped termination, usually colorless to pale yellow or pink, with hardness 7-7.5 and a white streak.
Danburite has poor cleavage, conchoidal fracture, and a high luster sometimes verging on greasy. It can be distinguished from topaz, which has perfect basal cleavage and is denser, and from quartz, which has hexagonal symmetry and conchoidal fracture without danburite's chisel terminations.
Danburite's orthorhombic form, striations, and characteristic crystal tips help confirm identification; clear faceted stones can be confused with white sapphire or topaz, separable by hardness and optics.
Uses & significance
Danburite is used as a collector's mineral and, in its cleaner form, as a faceted gemstone. Transparent yellow and colorless stones are cut into attractive gems prized for their brilliance, though their relative softness compared to sapphire and modest fire keep them as collector and connoisseur stones rather than mainstream jewelry.
It has no major industrial use, though it is a boron-bearing mineral of scientific interest.
In the metaphysical community danburite is heavily marketed as a high-vibration "angelic" stone for spiritual connection, peace, and the heart and crown chakras, though these claims are not scientific. Its value lies in crystal quality, clarity, color, and size.
Frequently asked questions
Where does danburite get its name?
It is named after Danbury, Connecticut, USA, where it was first identified and described in 1839.
Is danburite a gemstone?
Yes, clear yellow and colorless danburite is faceted into gems, though it is mostly a collector's stone rather than a mainstream jewelry gem.
How can I tell danburite from topaz?
Topaz has perfect basal cleavage and is denser; danburite has poor cleavage and distinctive wedge-shaped crystal terminations.
What colors does danburite come in?
Most often colorless or white, but also pale yellow, pink, and lilac.
Is danburite hard enough for jewelry?
At 7-7.5 it is reasonably durable, though softer than sapphire; it suits pendants and earrings more than heavily worn rings.
Danburite guides
In-depth guides for identifying, valuing, and understanding Danburite.
