1. What is an Opal: An opal is a mesmerizing gemstone famous for its ability to flash a rainbow of brilliant colors that seem to shift and dance as you turn it in the light: it is a moving rainbow in a rock.

2. Built from Water: Unlike most gemstones that form deep underground from heat and pressure, opals are born from wet silica-rich water that drips into cracks in the earth and slowly hardens over thousands of years: they are made of stone and water.

3. Tiny Sphere Magic: The magical rainbow colors in an opal aren't actually pigments, but rather tiny microscopic spheres of silica stacked in neat rows that bounce and bend light waves in all directions: it is a natural prism.

4. Australia's National Gem: Australia is the opal capital of the world, producing over 90 percent of all the precious opals on Earth, with many miners even living in underground homes to escape the hot desert sun: they rule the opal world.

5. Dinosaur Fossils: Sometimes, mineral-rich water replaces the bones of ancient creatures buried in the ground with opal, creating sparkling, multi-colored dinosaur teeth and bones: it turns fossils into treasures.

6. Water-Holding Rocks: Because they formed from water, opals can actually contain anywhere from 3 to 21 percent water inside their structure, making them much softer and more delicate than diamonds: they are wet gemstones.

7. Birthstone Brilliance: Opal is the official birthstone for the month of October, making it a wonderful and sparkly gift for anyone with an autumn birthday: it is a bright fall treasure.