Geological & Scientific Properties | Danburite
Danburite is a lesser-known yet attractive mineral that has gained attention in both mineral collecting and gemstone markets. It is appreciated for its clarity, luster, and durability. Here are the key geological and scientific properties of Danburite specimens:
Chemical Composition and Structure:
- Composition: Danburite is a calcium boron silicate mineral with the chemical formula CaB₂(SiO₄)₂.
- Crystal System: It crystallizes in the orthorhombic system, forming typically elongated, prismatic crystals.
Physical Properties:
- Color: Pure danburite is colorless, but it can also be found in shades of yellow, pale pink, or brown due to impurities.
- Hardness: It has a hardness of about 7 to 7.5 on the Mohs scale, making it quite durable.
- Luster: Danburite typically exhibits a vitreous (glass-like) to greasy luster.
- Transparency: This mineral is generally transparent to translucent.
- Cleavage and Fracture: Danburite has poor cleavage and tends to fracture in a conchoidal to uneven pattern.
Optical Properties:
- Refractive Index: The refractive index of Danburite ranges from 1.627 to 1.641, which is relatively high and contributes to its brilliance when cut.
- Birefringence: Due to its orthorhombic crystal structure, Danburite exhibits noticeable birefringence.
Geological Occurrence:
- Formation: Danburite typically forms in high-temperature hydrothermal environments, particularly in cavities within country rocks and in contact metamorphic deposits.
- Associated Minerals: It is often found in association with minerals such as quartz, calcite, dolomite, and various sulfide minerals.
Major Deposits:
- Danburite was first discovered in Danbury, Connecticut, USA, which is the source of its name. Other significant deposits have been found in Mexico, Madagascar, Japan, Myanmar (Burma), Russia, and Switzerland.
Danburite's combination of clarity, hardness, and subtle colors make it a desirable specimen for collectors and a suitable material for jewelry. While it is not as widely known as some other gemstones, its unique properties and the beauty of well-formed crystals have garnered appreciation among enthusiasts.
