With gold prices high, there's a boom on for small pieces of the precious metal.

"Everbody's getting into the act," says Margo Russell, editor of Coin World tabloid, the Wall Street Journal of the gold- and silver-coin markets. The Mexicans, she says, are pushing their nice-looking gold coins through such outlets as Citibank in New York. The South Africans are pushing theirs through a massive U.S. advertising campaign, and even the U.S. Mint is out with its own "small" gold piece -- the half-ounce Marian Anderson medallion.

Apparently, all kinds of people what a piece of gold even if they can't afford the official 1-ounce trading size. So, the marketing theory goes, mint small pieces of gold and bring in customers who just want to say they own some or want to wear it.

The trouble is, you can get all sizes, shapes, weights and purity of gold. Some places sell the metal with a lower "premium" than others. This means you don't have to pay a large markup over the day's "spot" prices for one ounce on the official exchanges.

The main things you want to know when you're buying are the actual net weight of the unalloyed gold and the "premium" you're paying over the daily sppot price. This can become tricky when an advertisement gives the weight in grams -- such as a 1-gram ingot (very small -- like a longish fingernail) or 5-gram ingot.

As a rule, you have to pay a bigger premium for the smaller pieces of gold. This is natural because relative mint costs are higher. But some gold pieces have lower premiums than others, depending on the seller. On one day recently, the 1-ducat piece from Austria was being sold at only a 7 percent premium.

This coin, which is quite thin, sold for $80 on the day I phoned in for quotes. Its weight is listed at 0.1109 ounces or 3.45 grams.

On the other hand, a tiny 1-gram ingot sold for $36, which included a whopping 65 percent premium over the spot price.

Then you get into the coin-versus-medallion-versus-ingot routine. Official government coins seem to have the best value because they're easier to trade and to translate into, fixed, international, daily quotes. But medallions with bullion weights of gold, such as a 1/2-ounce, can also be translated into daily quotes. So can ingots if they're in fractions of an ounce (or in grams with a good translator on the line).

You can get more purchase information from a well-stocked coin shop. If you have any difficulty with price, weight and premium quites, try calling -- toll-free -- one or all of the following:

Citibank in New York specializes in Mexican gold coins. A two-peso piece sold for $40 on the day I called. For quotes and a free booklet, call 800-223-1080.

Deak-Perera in New York sells all kinds of small gold coins, ingots and medallions. Call 800-223-5510.

U.S. Mint is selling half-ounce Marian Anderson medallions through order blanks in post offices. For price quotes, call 800-368-5510.

Q. I wan to buy a little gold coin or bar to be made into a necklace. Will it ruin the value of the coin if I have a loop put on it for a gold chain?

A. Coin collectors say it's not wise to make necklace pendants out of rare coins. The wear and tear can dramatically drop the value.

But bullion coins and small ingots are fair game. The value of these coins is in their gold weight, not ther rarity. Don't try to fuse a loop on the coin. You need a 14-carat (tough alloy) frame around the coin (or little ingot) with a small loop for the chain on top.

A jeweler can do this, but you might get a better deal from a company that sells a lot of framed coins or ingots. Compare prices.

Q. I have a Little Orphan Annie cup and a game (board and spinner). They're both at least 50 yars old and in excellent condition. How can I find out what they're worth?

A. Ask your main library's reference librarian for help. There are all sorts of hobby and antique books and magazines available. the editors of these publications may know of collectors' clubs in your area. Or you can get prices from the advertisements. There's no fixed market price. You haggle.