A recent Phillips auction in New York saw an “extremely rare” Patek Philippe watch with a Tiffany Blue dial sell for $6,503,000 to an anonymous buyer, IDEX Online reports.

The stainless steel Nautilus ref. 5711/1A-018 is the first of a limited run of 170 to be produced. The proceeds from the sale, according to the report, will go to the global environmental organization Nature Conservancy. The remaining 169 pieces will be sold at Tiffany & Co. boutiques where Patek Philippe watches are also sold – New York, Beverly Hills and San Francisco.

According to Phillips, the watch is “without a doubt, amongst the most exciting, exclusive, and coveted examples of a Nautilus ever offered”.