10 Fascinating Facts About Iolite
Iolite is a mesmerising blue-violet gemstone with a rich history and unique properties. Though less well-known than sapphire or tanzanite, it has been cherished for centuries for its stunning colour shifts and practical uses.
Here are 10 fascinating facts about iolite that make it a standout gem!
The Largest Faceted Iolite
The largest known faceted iolite weighs an impressive 855 carats and is housed in the Natural History Museum of Denmark in Copenhagen. This exceptional specimen showcases iolite’s beauty on a grand scale, making it a must-see for gemstone enthusiasts.
Often Found Alongside Garnets
Iolite is frequently discovered near garnet deposits, as both minerals form under similar geological conditions. They are often found in metamorphic rocks, which have undergone prolonged periods of intense heat and pressure.
Finland Has an Abundance of Iolite
Finland is home to some of the world’s most significant iolite deposits, particularly in the Koli National Park region. Finnish iolite has been explored for both jewellery and industrial use, with its strong pleochroic properties making it an interesting gemstone to study. The country’s commitment to sustainable mining practices also adds to iolite’s appeal.
Iolite's Colour Can Shift in Different Lighting
One of iolite’s most intriguing features is its ability to shift colour depending on the lighting. In daylight, it typically appears blue-violet, but under warm incandescent lighting, it may take on a golden-brown hue. This dynamic quality makes iolite a fascinating choice for jewellery, as it appears to change throughout the day.
Pleochroism Made It Difficult for Early Cutters
Iolite exhibits strong pleochroism, meaning it shows different colours when viewed from different angles. While this gives the gem its captivating depth, it also makes cutting it quite challenging. Lapidaries have to carefully orient the stone to bring out its best colour, as cutting along the wrong visual axis could result in a dull or murky-looking stone.
One of the Rarest Blue Gemstones
Although iolite is not as famous as sapphire or tanzanite, it is one of the rarest naturally occurring blue gemstones used in jewellery. High-quality iolite is less commonly found on the market, making it a unique and underappreciated choice for collectors. Its affordability compared to sapphire makes it an excellent alternative for those who love blue gems.
Ancient Civilisations Used It as an Optical Filter
Beyond its beauty, iolite was historically used in early optical experiments. Its ability to filter light made it useful for testing how different wavelengths passed through transparent materials. Some historians believe early seafarers may have experimented with iolite lenses to improve visibility in bright sunlight.
Once Considered an Amulet for Travellers
In ancient times, iolite was believed to be a protective stone for travellers. Some cultures thought it could guide lost souls home, making it a popular talisman among explorers and sailors. This belief aligns with its use in Viking navigation, strengthening its reputation as a guiding stone.
It Was Once Called "Water Sapphire"
Early traders often referred to iolite as "water sapphire" due to its deep blue colour. It has also been nicknamed "poor man's sapphire" because of its affordability, despite being rarer than sapphire itself. These names highlight both iolite’s beauty and the that a gems price is in big part down to marketing, not availability.
Viking Compass Stone
Perhaps the most famous fact about iolite is its use by the Vikings as a navigation tool. Vikings used a tool know as the "sunstone" to help them locate the sun’s position on cloudy days by filtering polarised light. Iolites probable connection to this navigation tool has earned it the reputation of being a viking compass.
Click Here to read more about the Viking sunstone.
From its historical significance to its mesmerising optical effects, iolite is a gemstone full of surprises. Whether you're drawn to its Viking heritage, its colour-changing nature, or its rarity, iolite is a fantastic addition to any gemstone collection!
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