Professional Jeweler Archive: A River Runs Through It

September 2001

Gemstones & Pearls/Gemology


A River Runs Through It

The Shangri-La opal features a river that alternately flows or runs dry – depending on the light


Utopians will love this opal. When James Hilton wrote his classic tale Lost Horizons, he described a paradise lost in the Himalayan Mountains where people could live forever. Detailed in the story is a steel blue river that runs through the valley of Shangri-La.

When miners at Lightning Ridge, Australia, discovered this black opal over 40 years ago, they saw in its play-of-color the hues Hilton described in his fictional paradise – even the winding blue river. They named it Shangri-La and even registered it with the Australian government.

David Baitel of Opex Opal, Santa Barbara, CA, who now represents the opal for sale, recently allowed Professional Jeweler to photograph the gem under various lighting conditions to capture images of the hidden valley and river.

The play-of-color “river” flows from the top central part of the gem down through verdant hills and valleys. By angling the lights differently, the “river” appears to dry out, replaced by even greener valleys and pastures.

Play-of-color occurs when rays of light enter an opal, bend slightly and then reflect and refract from millions of microscopic silica spheres combined with water (an opal’s composition). A similar mechanism causes the multicolored oil-on-water effect on rainy pavements. It’s called the interference-of-light effect.

With opals the effect is three-dimensional, so changing the angle of the light or viewing the gem from a different angle changes the depth of color or changes the color entirely.

Opex Opal, Santa Barbara, CA; (800) 352-4445.

– by Robert Weldon, G.G.


A blue “river” play-of-color runs from the top central portion of the 270-ct. Shangri-La opal.

Photo by Robert Weldon.

When lights are angled differently, the river appears to dry out and the “hills and valleys” gain richer color. Gem courtesy of Opex Opal.

Photo by Robert Weldon.

Copyright © 2001 by Bond Communications