Costco, the discount US warehouse wholesaler, is offering a deep discount on a diamond ring. The 6.77-carat D color, Internally Flawless diamond solitaire is selling for $1 million, as opposed to the original $1.6 million.

The ring's diamond has been certified by both the GIA and IGI gemological laboratories.

While better known for selling household goods and food in bulk, Costco has been dealing in diamonds for a number of years. In October 2010, Jeweller Magazine reported that the chain's worldwide diamond sales for the 2009-2010 fiscal year approached 80,000 carats. Sales included diamond jewelry set with unusually large stones that commanded six-figure prices: diamond rings set with 8.55-carat oval-shaped diamonds for $213,200; 10.04-carat diamond earrings with a price tag of $201,000 and cushion-cut 7.06-carat diamonds at a cost of $193,800 apiece.

In May 2005, Costco sold a 12.19-carat yellow diamond ring valued at over $264,000 for $180,000.