The Arabian nomads believed Opals were magic stones sent from heaven, infused with lightning, and fell from the sky during thunderstorms.
We mostly use lab created Opals, which are chemically very similar to natural Opals. They are grown in a lab for around 12 months using approximately 80% Silica (what natural opals are composed of) and 20% Resin, until a glimmering stone is formed which is much more durable than a natural opal.
Will state in description if natural.