While Moonstone may sound like something that's found in space (or at least in a meteorite) it’s actually the most well-known member of the feldspar mineral family, which also includes Amazonite and Sunstone.
Moonstone’s most famous trait is its adularescence, which makes it a phenomenal gem, similar to Opal or Star Sapphire. While Opals display play-of-colour, Moonstone’s phenomena is a misty glow that makes the surface of the gem appear to glow. It's a unique effect, usually seen in a blue hue, that rolls across the gem depending on angle you view it at. Appropriately, the original name for Moonstone was actually “Adularia,” which came from a city in Switzerland, Mount Adular, which was one of the first sources of the best quality Moonstones.
The most valued type of Moonstone is transparent, colourless, eye-clean, and features a vivid blue adularescence. In some cases, adularescence can also feature striking rainbow colours. It's also possible for Moonstone to exhibit other phenomenal effects, including asterism, like Star Sapphires, and chatoyancy, like Cat’s Eye gems. If that wasn't versatile enough, they can also be found in a wide variety of colours, including white, yellow, brown, grey and black. They’re most often cut into beads or cabochons, however they can also be carved into various shapes and cameos, including popular face of the moon designs.
Its beautiful colours and special effects have always ensured Moonstone's wide fanbase, especially as one of the birthstones for June. However, it was particularly popular during the Art Nouveau period (1880-1915) including the Arts and Crafts movement, and again in the 1960s. The seemingly mystical and watercolour-like stone was perfect for the dreamy and romantic jewels of the time with floral and astrological themes, including those by late 19th century designers such as René Lalique and Louis Comfort Tiffany.
Like many gems, the best qualities of Moonstone are often found in Sri Lanka, however other sources include India and Myanmar. Moonstone is a 6-6.5 on the Mohs Hardness Scale, making it a softer gem that should be worn and stored with care in order to avoid scratches and cleavage (splitting), especially when wearing it in a ring. Overall, Moonstone is a lovely dream of a gemstone with mystical qualities which have been appreciated throughout history. Regardless if you have a June birthday or not, it's an excellent addition to any gem lover's collection.