The third birthstone for June is the moonstone. It is usually an almost colourless, translucent to transparent stone but they have gorgeous sheen. There are also grey moonstones which also have the identifying sheen. Moonstones belong to the Feldspar family, along with amazonites, labradorites and sunstones. They have an opalescent or adularescent sheen which can be a blue or white. You may see stones called rainbow moonstone but they are more properly colourless labradorites. The stone is mined in India, Sri Lanka, Myanmar, Tanzania, Kenya, Norway, New Zealand and Australia.
Historically, they are linked to worship of the moon and some Victorian jewellery contains moonstones carved with the face of the man in the moon. They were a popular gemstone in the Art Nouveau and Arts and Craft periods from the 1880s up to WWI.
The stones are usually cut as cabochons, with the domed top. Moonstones with a bluish sheen are the most sought after. They are usually not subject to much treatment although they can be coated to achieve the blue tint and there have been white synthetic spinels produced as imitants.
They have a hardness of of 6 to 6.5 in Mohs’ scale of hardness so they can show some scratches and wear but they are still a good stone to use for jewellery.