Today was a stellar day - after walking for 4 hours I feel like I'm finally tired enough to sleep more than five hours! Last night I had a nightmare but I'm used to them now, so they hardly phase me during the day anymore.
In our business class we were asked to bring an object we value, the one thing we would save in a fire. I chose the black opal my parents bought me for my eighteenth birthday. They imported the stones from Australia and then had a jeweler make the necklace around them. Did you know opals of any kind are one of the few stones people say "like to be worn"? It's because of their water content, somewhere between 3%-10% though they can be has high as 20%. Of course, if you take them into the cold or extreme heat they start to crack because of water expansion and contraction. So keeping them at a steady temperature, is ideal. While opals are a mineraloid, they do have an internal structure that allows it to show a variety of colours within the stone. At micro scales precious opal is composed of silica spheres some 150 to 300 nm in diameter in a hexagonal or cubic close-packed lattice. These ordered silica spheres produce the internal colors by causing the interference and diffraction of light passing through the microstructure of the opal. It is the regularity of the sizes and the packing of these spheres that determines the quality of precious opal. Cool, right? Opals are insane, and I'm so glad they're my birthstone. The ones from Lightning Ridge Australia are considered the finest, but in general Australia exports 90+% of opals in the market.
I didn't explain all that to the class, but, y'know, the information is kinda interesting. All I had for dinner was a peanut butter 'n jelly sandwich and baked beans...maybe I should do groceries. Nah.
