The gemstone is known for its "play-of-color," or ability to shift hues. Rough opals appear white, but once polished, their surface shines a rainbow kaleidoscope. Opals can be found across the ...

The equipment needed to mine and cost to register your claim can be extremely expensive, between $100,000 and $150,000, but there's no guarantee that miners will find black opal. Once rough opal ...

Following is a transcript of the video. Narrator: High-quality black opal can cost over $10,000 per carat, making it one of the world's most expensive gemstones. But mining black opal isn't easy.