Before we can begin to talk about June’s birthstone, we need to discuss the term adularescence. It is what moonstone is known for, and more or less how it got it’s name.
Moonstone is part of the feldspar group of minerals which make up about 60 percent of the earth’s crust. You would have come into contact with these minerals as they are used as flux agents in ceramics and glass production and as functional fillers in the paint, plastics, rubber and adhesive industries. Or you would have held a moonstone or labradorite in your hand and noticed the play of light as you turn the stone, almost like the moon reflecting off water, hence the name of moonstone.
Adularescenece is this light phenomenon, and it is caused by light scattering between microscopic layers of feldspar. Moonstone is composed of two feldspar minerals, orthoclase and albite. When it is formed these two minerals are intermingled, but during the cooling process the two minerals stack into a multitude of alternating layers causing the unique light effect.
Thus Hindu mythology states that moonstone is made of solid beams of the moon’s light, and has been held in high esteem and associated with the moon by most ancient cultures that came across it. Moonstone was even a great favourite of the hippie culture of the sixties. It is associated with love, passion and fertility, and believed to bring the wearer good luck. The ancients believed one could see into the future with a moonstone in the mouth during a full moon.
Moonstone comes in a variety of colours from translucent to grey, yellow green or pink. The very best are a clear stone with a blue luster found in Sri Lanka, although Brazil, Myanmar and India are also prolific producers, the latter the best source for rainbow moonstone. Here in Africa Madagascar and Tanzania also yield good quality moonstone, but being an abundant feldspar mineral small quantities are found in many countries across the world.
Moonstone comes in at between 6 and 6.5 on the Mohs Hardness Scale, but it is quite a delicate gem due to it’s cleavage. Cleavage is a term used to describe the susceptibility of a gem to break across its internal planes, and with moonstone made of so many different layers one can understand why. Therefore moonstone is not a good idea for an engagement ring that will be worn daily, and is more often used as pendants and earrings.
In modern times moonstone reached its pinnacle during the romantic Art Nouveau era when famous designers such as Rene Lalique and Louis Comfort Tiffany used these beautiful gems in custom jewellery. Today moonstone is still a firm favourite for those in the know, especially rainbow moonstone. Below are a few pictures with links to some of our favourite pieces of jewellery from the website.
Until then please stay safe,
JD and Jay.