Alaska's Other Minerals.

• Author: SCHMITZ, RICHARD F.

All that glitters is not gold. Alaska's home to a variety of valuable minerals.

Last century, Alaska miners pursued rich gold placer deposits and black seams of coal. This century, Alaska's miners will increasingly seek out titanium sands, palladium placers, kimberlite pipes or niobium nuggets. There's gold in the hills to be sure, but increasingly valuable titanium, rare earths and, particularly, metals from the platinum group are even now beginning to catch more and more attention from the mining industry here in Alaska.

Similarly, Alaska mines are targeting such products as calcium carbonate, high-quality slab marbles and-just plain hard rock. A quarry on Annette Island under development by the Metlakatla Indian Corp. contains, well, hard rock.

"Surprisingly, it's hard to find rock that is unfractured and stands up to abrasion, rock that's suitable for heavy duty rip rap," said Dick Swainbank, development specialist with the state division of mining and minerals in Fairbanks.

A handful of geologists are convinced Alaska could be the source of diamonds--found typically in association with a geologic formation called a kimberlite pipe. Kimberlite has been found in the Northwest Territories of Canada, and in the 1990s the discoveries there sparked a staking rush equal to that of the Klondike a century earlier. In Alaska, raw diamonds have occasionally turned up in placer claims in the Circle City area.

"It's one thing that's been underexplored, for sure," said Mining Consultant Scott Petsel. "They're (kimberlite pipes) pretty hard to find-they're just small circular blocks sticking up in the middle of nowhere. It's like finding a doughnut hole in the middle of the tundra. But I'm sure some day we'll find (the pipes) in Alaska."

There have been recent rumors of diamonds found in the 40-mile and 60-mile country of the Yukon River, Swain-bank said. "And in the Yukon, there have been recent finds of emeralds--in association with geology that extends into the Tok district."

Metals are generally found in certain groups. Gold, for example, is often associated with tin and bismuth. Nickel is associated with lead and zinc--and sometimes barium and cobalt. And then there's the PGMs--Platinum Group Metals--which include such rare metals as osmium, iridium and ruthenium.

Another Such group is the so-called rare earths. Prince of Wales Island, in Southeast Alaska, is the location of Bokan Mountain, one of the richest rare earth deposits in the world...