With complete transparency, petalite features a glassy finish that makes this stone highly collectible.
Petalite is a rarely seen stone, often sought after by collectors. Featuring a clear, eye-clean transparency, its vitreous luster makes it an ideal colorless stone. While the clear material is preferred in gemstone specimens, petalite can also be found in grayish-white to faint pinkish colors. Rarely are these types used as a lapidary material.
As a mineral, petalite is mined for its lithium content. Lithium is a rare metal, with uses ranging from commercial to medicinal. While it contains less lithium than many related materials, such as kunzite, the rarity of the element ensures that most petalite is processed as an ore and its lithium extracted. These factors, alongside its rare occurrence, means that gem-quality petalite rarely makes its way to market.
How Did Petalite Get Its Name?
• Petalite’s name derives from Greek roots. The Greek word petalon means “leaf,” and this is an allusion to perfect basal cleavage petalite possesses. José Bonifácio de Andrada, the Brazilian naturalist who discovered petalite, thought this quality resembled leaves and named it accordingly.
Why is Petalite also called Castorite?
• The name castorite has its roots in classical mythology. Originally, the mineral pollucite was discovered in Italy, in the mid-nineteenth century. It was named after the Greek and Roman figure Pollux, one of Zeus’s many sons. Alongside, another mineral was discovered and was named castorite, after Castor, twin to Pollux. Notably, the twins are the same that make the constellation Gemini. Over time, the use of castorite fell out of favor in preference to petalite.
Petalite is a highly rare gemstone and is not often used in jewelry, making it a collector’s gem. First discovered in Sweden, in 1800, it is only found in a few locations worldwide, including areas such as Australia, Brazil, Italy, and Sweden. Shop LC sources its supply from the Espirito Santo state of Brazil.
Mining Petalite in Brazil
Sources of petalite are scarce, and some experts suggest that the Espirito Santo supply will be depleted in the near future. As a lithium bearing mineral, sources of petalite are often found among other stones that contain lithium, such as kunzite, Xia kunzite, and tourmalines. Like many other Brazilian gemstones, petalite is found in crystal-rich granite pegmatites. Pegmatites are rocks that have crystals formed throughout their structure, often the result of volcanic activity and other natural Earth processes.
The rough material can vary in yield, but on average only ten-percent will find itself shaped, cut and polished into a stunning gemstone. Petalite can be a challenging specimen to work with, as it cleaves in an unusual way. Basal cleavage means that the gem can break into sheet-like pieces, so an expert’s hand is preferred when working with the stone. Not only that, but this means extreme care is necessary when setting this gemstone in prongs, with great precision required to make sure the gemstone is suspended correctly to aviod damage.
• Ranks 6 to 6.5 on the Mohs scale of hardness.
• The faceted material is transparent and colorless.
• Petalite undergoes no known treatments.
• May also be known as castorite.