A few weeks ago, I had the great pleasure to visit the world class Rice Northwest Museum of Rocks and Minerals, located 20 minutes west of downtown Portland. This museum was founded by Richard L. and Helen M. Rice in 1996 for the education and enjoyment of beautiful wonders of nature. They house not only the "Alma Rose" Rhodochrosite from the Sweet Home Mine in Alma, Colorado but also the largest opal-filled thunderegg in the world. Dinoaur eggs, countless fossils, metorites, and crystalized gold bigger than your hand are among the hundreds of other attractions.
As you know, natural earth pigments have been the focus of my studies over the past many months, so I was particularly attracted to specimens like lapis, malachite, and azurite. Shown here is a splendid chunk of azurite I purchased for my collection. This one is from Bisbee, Arizona but there are many locations in the world where it is mined, including Dzhezkgazgan, Kazakhstan.
This is an enlarged view and the piece actually measures a mere 1 and 1/4 inches or so. The greenish color here is malachite which is usually with the azurite in its natural form. The most brilliant particles of blue are sparse. I would guess this chunk would yield a paltry pea-sized piece of pigment, so it is easy to understand the high cost in its dry form.
Fascinating! Now I have to look up “thunderegg” and where opal comes from. Inside of eggs? I’m intrigued.