London--De Beers saw rough-diamond sales plummet 57 percent in the first half of 2009 as sightholders took less goods in an effort to clear out the pipeline and increase liquidity. In my opinion the value of diamonds is too volatile to consider for investment or collection purposes. I suggest you buy sculptural jewelry from artists that produce quality collectible jewelry. To find these jewelers peruse galleries and museums for the art jewelry that fits your style. An example of quality collectible art jewelry is the work of Shana Kroiz. Shana's work is shown at the Museum of Arts and Design in New York City. Pictured above are earrings from Shana's Peeciz collection.