Unfortunately Amazon.com does not publicize granular category sales data (sales, number of sellers, growth rates) but selectively shares highlights in its earnings announcements.

One exception is the jewelry category, and today Amazon announced today that its sales of diamonds have risen 75% YOY (rubbing salt in the eyes of countless third-party sellers that would like to sell their products in this gated category).

Selection for Amazon.com’s diamond jewelry collection expanded with 2,269 new styles launching in the third quarter, including an extensive number of styles of the black diamond collection. Top-sellers included a pair of 2-carat black diamond studs, the white gold Journey Curve ½-carat pendant and the yellow gold Journey Curve 2-carat pendant. Gemstones were very popular with Amazon customers in the third quarter. Over 240 new styles launched, including the top-selling white gold ruby and 2-carat diamond ring, a 14k white gold pink sapphire and diamond bracelet and 14k yellow gold four-prong round peridot stud earrings. Amazon.com’s Jewelry & Watches Store currently offers over 100,000 diamond jewelry and watch items, including 5,000 diamond watches, 16,000 pairs of diamond earrings, 22,000 diamond necklaces and 7,000 bracelets, to name a few.

Launched in August 2004, the jewelry category reported 100% growth in Q3′06 and 100% in Q4 ‘05. Don’t get me wrong, 75% is a great number, but an indication of a slowndown. I know a handful of very qualified jewelry sellers that have, so far, unsuccessfully tried to get into this category, and would add great product to Amazon to help maintain this growth — someone call me and we’ll get them launched.

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