15.1 days old moon.

99.7% illuminated.

THE BUSHFIRES ARE RAGING IN AUSTRALIA 🇦🇺 MANY CERAMIC STUDIOS OF MASTER CRAFTSMAN ARE BEING DESTROYED. 🔥 IF YOU CAN, PLEASE DONATE (even a little) TO HELP THEM, THEIR FAMILIES, THEIR CRAFT, THEIR LIVES.

Peter and Vanessa Williams, Mogo Pottery, NSW: lost everything 31 December 2019. Their home and studio and all the contents have been lost. They aren’t insured. Their home and studio were two heritage churches they had relocated and renovated. St Mary’s was 120 years old and St. Bernards was 130 years old.

www.gofundme.com/f/peter-and-vanessa-williams

Natural Mogok Burmese Ruby and Diamond Necklace

The Star of Asia

One of the most beautiful asteriated sapphires in the world, weighing in at a whopping 330 carats, it has excellent deep blue colour and a very sharply defined star (the main criteria of value in these stones). The optical effect comes from the light reflecting off needles of rutile, a titanium dioxide mineral that we covered at http://on.fb.me/1EXvics. As the corundum cools below a certain point, the atoms that had coexisted in a flux separate and form distinctive minerals, a process called exsolution. The aluminium oxide turns into the sapphire, and the needles of rutile (known as silk in the gem trade) form along three lines of direction that reflect the crystal structure of the sapph, and are clearly visible in the photo.

To reveal the effect stones have to be cut as cabochons, domed stones usually with a flat base for setting, and exposed to a bright light source. This stone has a history before it entered the Smithsonian gem collection in 1961, having belonged during the Raj era to the Maharaja of Jodhpur. Unfortunately for them, at independence and in the decades after, the pensions the Indian kings and princes had been promised when agreeing to join their princedoms to the new Indian republic never materialised, and many stunning gem collections were dispersed into the gem trade in order to put bread on the table.

The rough came from the ancient mines near Mogok in Burma, still a source today for some of the world's finest stones. Unlike most sapphires in the trade, star stones are not roasted in ovens very often, as one of the main reasons for doing this is to remove the rutile, improving the clarity and sometimes changing the colour, which would of course destroy the star. In ancient days, such stones were seen as protective talismans for travellers.

We did another post on a famous asteriated stone, the Rosser Reeves star ruby, also in the National gem Collection at http://tinyurl.com/lx88px4

Loz

Image credit: Chip Clark