The following report comes from Wired News correspondent Natali Del Conte.

Amazon announced on Tuesday that the company is selling 75 percent more diamonds this year than last year. What the retail giant won't tell you is whether all the jewelry it sells is "conflict-free," meaning the diamonds it contains are guaranteed not to have been brought to market through violence, human rights abuse, child labor, or environmental destruction.

Jewelers and human rights activists use the term "blood diamond" to refer to gems that have been mined and sold with the use of exploitative human labor practices, often in countries where the proceeds from diamond sales are used to fund bloody civil wars. Approximately 5 percent of all diamonds sold, and an unknown number of Amazon's, are blood diamonds.

"The only way to keep blood diamonds off the market is to certify all the conflict-free diamonds on the market," said Robert Cosentino, founder and executive director of The Conflict Free Diamond Council, an organization that works to promote conflict free diamond awareness in consumers.

While Amazon refused to give EPICENTER specifics on exactly how much diamond jewelry the company sells, its Jewelry and Watches section is currently offering more than 100,000 items with diamonds, including 5,000 diamond watches, 16,000 pairs of diamond earrings, 22,000 diamond necklaces and 7,000 diamond bracelets.

Tracy Ogden, a spokeswoman for Amazon, said on Tuesday that all diamonds on the site are supposed to be conflict free.

However, Amazon's jewelry product listings do not specify which diamond products on its site have been certified as conflict free. A search for "conflict free" within the Jewelry and Watches section returns only two results, one of which is not a diamond.

"If you ask me where the diamonds on Amazon diamonds store came from, I can't tell you, nobody can," Cosentino says. "The chances are good that they are conflict-free but that doesn't stop the blood trade with diamonds. You've just really got to start to demand that every single one of those diamonds is actually certified."

Without certification attached to specific products, how is a consumer to know that a particular diamond product is conflict free?

Ogden's response: Call customer service.