Earth Treasures: Bytownite
By Chisom Ibemere
Bytownite is a form of feldspar named after the city of Bytown (now Ottawa) in Canada. It was first discovered in Canada in 1835.
It is a calcium-rich member of the plagioclase feldspar group. Bytownite is one of the intermediate members of the series, ranging between anorthite and labradorite.
Bytownite is typically found in intrusive igneous rocks, particularly in gabbro and anorthosite.
It occurs in various locations worldwide, including Canada, Norway, Russia, the United States (especially in New York and Maine), Madagascar, and India.
Bytownite is used majorly as a gemstone and in the jewelry industry. However, it is relatively rare and not widely known or utilized in the jewelry industry.
It is often faceted and used as a collector’s stone or incorporated into unique and custom-made jewelry pieces.
Bytownite has a composition that falls within the range of 70-90% anorthite and 10-30% albite. It has a hardness of around 6 to 6.5 on the Mohs scale.
Bytownite typically exhibits a yellowish to brownish color, but it can also be colorless or pale yellow. It has a vitreous luster and a transparent to translucent appearance.
Bytownite is often distinguished by its high refractive index and moderate dispersion, which allows for good brilliance and fire when cut into gemstones.
Bytownite is not as widely recognized or sought after as some other feldspar gemstones like labradorite or moonstone. Its global value is relatively modest, and prices for bytownite gemstones tend to be lower compared to more popular gemstones.
However, some collectors and gem enthusiasts appreciate its rarity and unique beauty, contributing to its value. Overall, the global demand and market for bytownite gemstones are not as extensive as for other feldspar varieties.