(IDEX Online) - A 38-carat Goloconda diamond that once belonged to socialite Christina Onassis is being offered for sale with a $7.5m price tag.The pear-shaped Type IIa, D-color, VVS1-clarity stone was set into a pendant necklace by Jacques Timey for the King of Diamonds, Harry Winston.The platinum and white 18K gold necklace (pictured) has an additional 20.00 to 25.00 total carats, of G color and VS clarity. Goloconda diamonds, mined in India until the 17th century, are prized for their remarkable quality, whiteness and clarity.The diamond was a gift It was a gift to Christina Onassis from her father Aristotle Onassis, Greek shipping magnate who died in 1975.It's being sold by M.S. Rau, specialists in fine art, antiques and jewelry, in New Orleans, Louisiana, USA.