Pink Opal: 8 Honest Facts About the Andean Stone
Pink opal is a variety of common opal, opal without the flashing "play-of-color" seen in precious opal, valued…
Black Opal: The Rarest Opal, and Why It Isn’t Actually Black
A truly black opal, one that's completely, uniformly dark with no color at all, would be worthless. That's…