BY STEVE VOYNICK
Tiny crystals of green chromium diopside, specific gravity 3.28, often turn up in gold-pan concentrates.
THE ARKENSTONE,
IROCKS.COM Gold panners tend to categorize their pan concentrates as either gold or “black sand”—and to discard the latter without much of a second look. And that’s too bad, because pan concentrates often consist of a diverse array of minerals which, viewed under a 10X loupe, display colors and forms that are keys to their identification. At the least, pan concentrates are telltale indicators of upstream geology.