When diamonds aren't forever.

Here are tips for auctioning off your gems

Do you have an old diamond ring you'd like to sell, or some jewelry you've inherited that you'd like to auction?

Increasingly, auctions--whether held in traditional auction houses or online--are ways to easily reach an audience of buyers.

But before you visit an auctioneer, there are several steps that you should take to determine the value of your diamond.

First, your item must be assessed by an appraiser. That person will have the complex job of determining the ring's value based not only on the 4Cs (the color, clarity, cut, and carat weight) but also on the quality of the workmanship. The appraiser can also determine if it was made by a prominent maker, like Tiffany & Co., for example.

"Only a trained eye can distinguish the difference in stones once they are in settings, so an appraisal accompanying a piece is an added incentive for the buyer," says Joanna Brannock, a contributing editor for jewelry at BiddersEdge.com (www.biddersedge.com), an online portal to more than 200 auction sites.

Based on market value and the condition of the stones, your diamonds may appreciate or depreciate over time due to whether or not the jewelry has been damaged, its rarity, or if it has remained in its original condition.

After you have determined the value of your stone, you must decide what medium you will use to sell it. Christie's and Sotheby's are well-known auction houses, however affected by the recent scandals surrounding them.

"Usually with auctioneers, you can expect non-estate pieces to get between a quarter to one-half of the retail price it sold for when it was new," says James V. Jolliff, executive director of the National Association of Jewelry Appraisers (410-897-0889) in Annapolis, Maryland.

Second, decide what type of audience you are looking for. Would you like a mass audience, or do you possess a unique piece of jewelry that you only want to be considered by serious collectors?

If you are going to use online auction sites such as eBay or Yahoo!, find out how pieces similar to yours are listed and if the site receives a portion of the sale. Although eBay allows you to register for free, it charges 25 cents to $2 to list your diamond, and once it is sold, their commission is about 5%, depending on the final closing price.

"Make sure you are very descriptive in listing your diamond, provide very good images, and be honest about what you have," instructs Shira Levine, senior manager of jewelry and gemstones for San Jose, California-based eBay.

Before you auction your diamond, be sure that the auction house has a means to "rate" the seller for potential buyers, something both eBay and Yahoo! have. "We have a feedback rating system where buyers and sellers are given a point every time they get positive feedback," explains Levine. Also, make certain there are protection mechanisms, such as insurance and escrow services, on the site. There should also be a variety of payment systems, such as Billpoint, an electronic payment service that eBay makes available, which allows sellers to accept credit cards or electronic checks, or PayPal.

"The important thing to remember is to educate and inform yourself. Ask questions until you are completely satisfied," advises Brannock.

CUT

More than any other quality, cut determines the fire and brilliance of a diamond.

COLOR

A stone's beauty and value usually increase dramatically the more colorless it is. The spectrum ranges from light yellow, "Z," to totally colorless, "D."

CLARITY

It is possible to find some imperfections in almost every diamond --inclusions--that affect a diamond's value. Clarity grades range from "I" (imperfect) to "FL" (flawless).

CARAT

Carat is the standard measure of a diamond's weight. But size alone is almost meaningless unless you consider cut, clarity, and color.

Appraisal Associations

* American Gem Society 8881 West Sahara Ave. Las Vegas, NV 89117 702-255-6500; fax: [phone] www.ags.org

* American Society of Appraisers 555 Herndon Parkway, Suite 125 Herndon, VA 20170 703-478-2228 or 800-272-8258 fax: [phone]; www.appraisers.org

* Appraisers Association of America Inc. 386 Park Ave. So., Suite 2000 New York, NY 10016 212-889-5404; fax: [phone] www.appraisersassoc.org

* International Society of Appraisers 16040 Christensen Rd., Suite 102 Seattle, WA 98188-2929 888-472-4732 or 206-241-0359 fax: [phone]; www.isa-appraisers.org