American Eagle silver and gold bullion coins have been the cornerstone of the U.S. bullion market since they made their debut in 1986.

Walk into any coin shop or show, check eBay or any bullion trading Web site, and one thing was certain. There would be plenty of American Eagle bullion coins available. It didn't matter if a shopper was looking for a single example or 1,000 pieces. The order could be filled swiftly.

That kind of predictable commerce has changed dramatically in recent weeks.

With irregular U.S. Mint suspensions of minting for both American Eagle silver and gold coins, supplies of new pieces have diminished during a year when demand for bullion has grown substantially. In normal times, bullion purchased in the secondary market would keep supply and demand in balance, but not today.

Veteran "goldbugs" and new investors alike are clinging to their bullion coins and buying more as they can find them. Current spot prices of less than $750 an ounce for gold and less than $10 for silver have no relation to real world prices for American Eagles and other bullion coins because demand is outstripping supply.

As an example, eBay consignors are routinely drawing bids of $16 to $20 plus postage per 1-ounce silver American Eagle. Those who want a less expensive alternative might find privately minted 1-ounce bars and rounds or pre-1965 circulated silver for $13 an ounce and up. Anyone who insists on only American Eagles may find nothing.

One well-known bullion broker and American Eagle supplier has little more to offer than odd lots of Mexican gold, Austrian Philharmonic quarter-ounce gold pieces and small batches of old European fractional gold. Customers could have purchased unlimited amounts of American Eagle silver coins from the firm early in the year, but the business has almost no silver on its Web site today.

Premiums above melt for American Eagle gold bullion coins are somewhat higher than they have been in the past. Silver premiums are in the stratosphere. You can't rely on commodities exchange spot prices as a solid guideline to determine price. It comes down to a "value is in the eye of the beholder" scenario, and this unsettled situation may not change soon.