Conch pearls, Quahog pearls and Melo Melo pearls

Wow ! As you said, the conch pearl and diamond drop earrings look stunningly beautiful !!! Never seen anything like that before. Little wonder the pair sold for £5,000 more than the upper pre-sale estimate of £15,000.

However, the price of £20,000 (US$ 31,500) does not come anywhere near prices realized by similar drop earrings incorporating nacreous pearls.

Yes indeed Sunil ! you are right. Let me give you some examples of drop earrings that registered fantastic prices at recent auctions.
1) Pair of Antique Natural Pearl and Diamond Ear Pendants, that sold for US$ 217,000 at a Christie's Dubai auction on April 29, 2008.
2) Fine Pair of Natural Pearl and Diamond Ear Pendants, that sold for US$ 157,000 at the same Christie's Dubai auction on April 29, 2008.
3) Pair of Art Deco Natural Pearl and Diamond Pendant Earrings, that sold for US$ 165,176, at a Christie's Geneva auction on May 12, 2010.
4)Marie Mancini pearl and diamond ear pendants, that sold for US$ 253,000 at a Christie's New York auction in 1979.
The following thumbnails are 1), 2), 3), and 4) above.

Thanks, for the information and comparison provided.

What about the fiery-orange melo melo pearls first recognized in the West in 1993 ?

Melo pearls are another class of non-nacreous pearls, produced by one of the species of melo volutes, such as Melo aethiopica, Melo amphora, Melo broderipi, Melo georginae, and Melo melo. These pearls were largely unknown to the Western World,until as recently as 1993, the year when the New York based jeweler, Bengamin Zucker, with the help of his friend, Kenneth Scaratt of the GIA, identified 23 of these deep-orange fiery pearls, sent to him by a Swiss dealer, who had purchased them from Vietnam. Zucker, then headed a small team of gemologists, who visited Vietnam, to find out more about these pearls and the sea snails that produced them. The result of this research on Melo pearls, was published in a 1997 article in the Smithsonian Magazine, that gave a big boost to the popularity of these pearls.
As a result of this publicity, a single fiery-orange melo pearl registered a record price of US$ 488,311, at a Christie's auction in Hong Kong in November, 1999. This was followed by the record sale of another single fiery-orange melo pearl for US$ 277,272 at a Christie's Hong Kong auction in April 2000. The unprecedented prices recorded by these pearls led to a rapid increase in the harvesting of melo volutes,in Vietnam, Burma, Cambodia and Thailand, resulting in an increase in the production of melo pearls, and a corresponding decrease in their prices, from hundreds of thousands of dollars to tens of thousands of dollars.
Some of the recent auction results are given below :-
1) A creamy orange colored melo pearl, with dimensions of 20.0 x 19.5 mm and weight 57.25 carats, sold at Bonhams Los Angeles sale for US$ 16,800, on December 7 & 8, 2008.
2) Another bright orange melo pearl of dimensions 11.0 x 10.5 mm and weight 10.28 carats, sold for $7,800 at the same auction.
3) However, the highest price ever recorded by jewelry incorporating melo pearls, was registered at a Sotheby's auction in Hong Kong in 2008. A melo pearl jewelry suite, consisting of a necklace incorporating 14 melo pearls, a pair of earrings incorporating two melo pearls in each earring and a ring incorporating a single melo pearl, combined with jadeite and diamonds, sold for a staggering US$ 692,000.
The thumbnails below represent 1), 2), and 3) above.

According to your information it appears that conch pearls and melo pearls are performing quite well at auctions, not as single pearls but when combined with other gemstones such as diamonds, jadeite etc. in exquisitely crafted pieces of jewelry,such as the conch pearl, melo pearl and natural pearl pendant necklace that sold for $54,886 and the melo pearl jewelry suite, combined with jadeite and diamonds, that sold for a staggering US$ 692,000.

You are correct to some extent, but unfortunately the difference in the pricing of nacreous pearl incorporated jewelry and non-nacreous pearl incorporated jewelry, that runs into the hundreds of thousands of dollars for the former and tens of thousands of dollars for the latter, still remains, and will remain so in the foreseeable future, until the public perception and misconception of associating nacreous pearls with the misnomer "true pearls" and non-nacreous pearls with the misnomer " not true pearls" is removed forever.
However, at least for melo pearls there appears to be a renewal in interest and a corresponding appreciation of prices as recorded by a rare melo pearl of 224 carats (896 grains), the second largest melo pearl on record and the 9th to be sold at an auction, that appeared at a Christie's Dubai auction on October 27, 2010, which fetched a staggering US$722,500, a world record price for a melo pearl sold at an auction, 4 times the lower pre-sale estimate of US$ 180,000 and almost 3 times the upper pre-sale estimate of US$ 250,000, which was purchased by a Chinese private collector.

How about the performance of the rare quahog pearls at the auctions ?

The extremely rare quahog pearls, produced by the saltwater clam Venus mercenaria (Mercenaria mercenaria), whose natural home is the north Atlantic coastline from Canada's Gulf of Saint Lawrence to Florida and extending into the Gulf of Mexico, are also a class of non-nacreous pearls. The occurrence of gem-quality quahog pearls of the desired lilac to purple color is extremely rare, and believed to be around one in 2 million. Like the conch pearls and melo pearls, quahog pearls too exhibit a type of chatoyancy, that produces a shimmering effect and sometimes an "eye effect" that enhances the beauty of the pearl, surpassing the beauty of some nacreous pearls. Due to their extreme rarity only a few quahog pearls of the desired color and quality had appeared at public jewel auctions, and it may be difficult to set a value for any high-quality quahog pearl. This was the difficulty faced by Alan Golash, the jeweler from Newport, Rhode Island, who owned the Golash Quahog Pearl Brooch, incorporating as its centerpiece one of the finest and largest quahog pearls on record, the "Pearl of Venus," when he wanted to dispose of this rare and exquisite piece of antique jewelry, of 19th-century provenance. As there had been no precedent of valuing a high-quality quahog pearl before, pearl experts had quoted values ranging from $250,000 to $ 1 million for the pearl brooch. The value of $250,000 is the most conservative estimate for the value of this rare quahog pearl brooch, and seems to agree with prices realized with other high-quality non-nacreous pearls, such as conch pearls and melo pearls.
However, four purple quahog pearls weighing 13.0 carats, 12.0 carats, 7.0 carats and 3.5 carats and having dimensions respectively of 12 x9 mm, 12.5 x 9.2 mm, 11.2 x 8.5 mm and 9.0 x 7.0 mm, that was sold at the Bonhams Los Angeles auction on December 7 & 8, 2008, for $60,000 might give some indication of the value of the Golash Quahog Pearl Brooch. The 14 mm "Pearl of Venus" has a shade of lilac color, and shimmer, clearly superior to any one of these purple quahog pearls, apart from the fact,the pearl also shows a rare and unique "eye" effect. The combination of all these rare characteristics and the Victorian era provenance of the antique piece, undoubtedly enhances the value of the Golash Quahog Pearl Brooch.
Thumbnails below 1) four quahog pearls sold at Bonhams, Los Angeles auction and 2) the Alan Golash Quahog Pearl Brooch.

I stumbled upon this stunning vivid-orange,papaya-colored,28.15-carat near-spherical melo pearl that appeared at the Bonhams Los Angeles, Natural History Sale, on December 11, 2011. A pre-sale estimate of US$ 55,000 to 65,000 was placed on the lot, but there were no takers !

These are two stunning conch pearls from the same Bonhams catalogue of the Los Angeles Natural History Sale of Dec.11, 2011. Lot No. 1302, a rare 2.84-carat, ovoid conch pearl with dimensions of 9.0 x 7.0 x 5.5 mm that sold for US$ 3,750 and Lot No. 1303, a 6.43-carat conch pearl with an unusual shape, somewhat heart-shaped or top-shaped, with dimensions of 10.0 x 9.5 x 8.0 mm, and a pre-sale estimate of US$ 3,500 - 4,500, but remained unsold.
Thumbnails below :-
1) 2.84-carat ovoid-shaped conch pearl.
2) 6.43-carat heart-shaped or top-shaped conch pearl.

The shimmering effect produced by chatoyancy in both the melo pearl and the conch pearls, look stunningly beautiful, and indeed surpasses the beauty of some nacreous pearls !!!

Thanks Anitap for posting the photos of the melo pearl and the conch pearls. I agree with Shah's comment on their stunning beauty, that surpasses the beauty of some nacreous pearls.
However, it is indeed surprising that the 28.15-carat, intense orange papaya-colored melo pearl, was not sold at the auction, despite its reasonable pre-sale estimate of USD 55,000 to 60,000. It was just one year ago, in October 2010, at a Christie's auction in Dubai, the second largest melo pearl in the world, weighing 224-carats and the 9th single melo pearl to be sold at an auction, fetched a world record price of USD 722,500, the highest ever realized by a melo pearl at an auction. The melo pearl was purchased by a Chinese private collector. The staggering price realized at the auction was believed to be an indicator that the rare melo pearl was finally gaining recognition as a valuable collectors item, on par with other nacreous pearls. Based on the price per carat of USD 3225 realized for the most expensive single melo pearl, the value of the 28.15-carat melo pearl works out to around USD 90,000. Hence, the pre-sale estimate of USD 55,000 to 60,000, is much less than the actual value of USD 90,000.

What was surprising, was that, despite the lower pre-sale estimate, there were no takers for the melo pearl. One possible reason for the lack of interest on the part of the buyers, was the smaller size of the melo pearl, which was in fact 8 times (224/28) smaller than the world's second largest melo pearl. However,what was lacking in size was compensated by the vivid orange color of the pearl which was superior to the color of the world's second largest melo pearl. Another possible reason for the failure to sell, was perhaps the venue of the auctions. It is of interest to note, that record prices for melo pearls were always registered in the Asian auction venues, particularly Hong Kong, a region where these rare pearls had been known and appreciated since very ancient times. Even in Dubai the successful record bid of USD 722,500 came not from an Arab but a Chinese collector. The melo pearl is deeply interwoven with the culture and beliefs of the people of China. Hence the great awe and respect in which the melo pearl is held, among these people, and the tendency to register record prices for these pearls in Asian venues. The 28.15-carat deep-orange melo pearl would undoubtedly do very well at Bonhams Asian venues of Hong Kong or Japan.

The 2.84-carat ovoid conch pearl and the 6.43-carat heart-shaped conch pearl, are indeed rare beauties of nature. The price of USD 3,750 realized by the ovoid conch pearl, compares well with the price of a conch pearl and diamond pendant necklace that sold for £3,750, at a Christie’s London auction on February 27, 2008 and another conch pearl and diamond pendant necklace that sold at a Christie’s auction in London on Dec.8, 2010 for $ 4710. The 6.43-carat heart-shaped beauty, ideal for a pendant setting, though unsold, would no doubt realize its potential at subsequent auctions.