Sotheby's first jewellery auction of 2011 took place this week in plenty of time for Valentine's Day, with heart-shape jewels featured in the Important Jewels sale, including a beautiful twin stone ring set with entwined emerald and yellow diamond hearts as well as an enamelled heart pendant made by Carlo Giuliano in the late 19th century.

The former is set with a heart-shaped diamond of yellow hue weighing approximately 2.80 carats, a heart-shaped emerald weighing approximately 2.60 carats, framed and flanked by round and square-cut near colourless diamonds weighing approximately .70 carat, and calibré-cut emeralds.

This had been estimated at $40,000-60,000, but excited bidders took it up to $110,500 (£68,353). However as expected the Guiliano piece marginally beat it, selling for $116,500 (£72,065).

A sumptuous platinum, sapphire and diamond ring also carried a $40,000-60,000 estimate but was taken home for $92,500 (£57,219).

Sapphire diamond ring

However, there was no doubt about the top lot: a classic Harry Winston ring set with a 16 carat emerald-cut diamond. Size 6½, with the main stone flanked by tapered baguette diamonds, it is accompanied by a GIA (Gemological Institute of America) report stating that the diamond is of I colour, VS1 clarity, justifying its listing of $300,000-400,000.

In fact, bidders decided that it was something of an underestimate, and they slugged it out until it was finally taken home for $662,500 (£409,811). This should make an excellent investment.

"We are delighted with the success of today's sale, which demonstrated the continued strength of the market for jewelry," commented Gary Schuler, Senior Vice President and Head of Sotheby's Jewelry department in New York.

"The auction saw particularly solid results for white diamonds, led by the Platinum and Diamond Ring from Harry Winston that brought $662,500, well in excess of its pre-sale high estimate. We saw bidding from a truly international audience, with many clients embracing participation through our online BidNow program, adding an exciting new element to our salesroom.

"Sotheby's jewelry sales in New York are off to a great start in 2011, and we now look forward to our auction of Magnificent Jewels on 14 April."