Moscow: Russian diamond-mining giant Alrosa has produced a "unique" diamond weighing 145.44 carats, which could fetch up to $1 million, the company said.
According to Alrosa's diamond-sorting centre, the gem discovered last month in Russia's coldest region Yakutia measures 35x20x26 mm and is octahedral in shape. It is clear with a yellowish hue.
In September 2012, Alrosa found an even larger diamond at another of its Yakutia mines, which it valued at more than $1.5 million and said could be split into several high-quality cut diamonds.
The latest find comes from deep within the Yubileynaya diamond pipe at Alrosa's Aykhalsky mining facility.
In October, the same pipe yielded an enormous industrial-grade diamond weighing 888.15 carats. That crystal, unclear and grayish-green in hue, was said to be the fourth-heaviest diamond ever produced in Russia.
Russia has the largest known diamond deposits in the world and Alrosa accounts for 97 percent of the country's production.
The principal regions of production are Yakutia, also known as Sakha, Perm and Arkhangelsk.
Alrosa accounts for 25 percent of the world's diamond production.
In 2011, the company produced 34.6 million carats of diamonds and sold $4.45 billion worth of its products. Figures for 2012, not yet fully calculated, were expected to total about 34.4 million carats and $4.5 billion.