The 76-carat Archduke Joseph diamond, described as internally flawless, comes from India's famous Golconda mines.

BBC: 'Perfect' Archduke Joseph diamond sells for $21m

Among the colored diamond highlights is an oval-cut fancy intense yellow, internally flawless diamond of 68.35 carats with excellent polish and symmetry.

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The two side diamonds are graded as D color and internally flawless.

FORBES: 48-Carat Diamond Ring Fetches $4.2M at Auction

The pear-shaped diamond is graded as D color, internally flawless clarity and the two side diamonds are graded as D color and internally flawless.

FORBES: 48-Carat Diamond Ring May Fetch $3.5 Million at Auction

Also commanding a powerful price was a 10-carat, D color, internally flawless pear-shaped diamond flanked on either side by a pear-shaped diamond, each weighing approximately 1.02 carats.

FORBES: 48-Carat Diamond Ring Fetches $4.2M at Auction

The auction house says it is one of the rarest and most famous diamonds in the world that combines an impressive size of 76.02 carats, perfect color, and internally flawless clarity.

FORBES: 76-Carat Archduke Joseph Diamond Expected to Fetch $15 Million

The top lot at the Oct. 19 sale is a rare, internally flawless pink diamond weighing 25 carats, set in an elegantly simple rose gold and platinum ring, flanked on either side by a petite pear-shaped diamond.

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