Where diamonds are common as muck

The Life: You've heard of the world's biggest diamond. But this is diamond's biggest world.

The planet 55 Cancri e is composed mostly of diamond. Courtesy nasaimages.org

You've heard of the world's biggest diamond. But this is diamond's biggest world.

An American-French team of astronomers reported this week that a planet known as "55 Cancri e" in the constellation of Cancer is composed largely of diamond.

The all-important question is, how much could this baby fetch on the open market?

Setting aside the rather considerable transportation and extraction costs (the planet is a 40-light-year commute, each way, and its surface is hot enough to boil lead), a rough calculation runs something like this:

- A carat weighs 200 milligrams.

- Although the price of rough diamonds varies greatly, a sale this month of rough diamonds from Lesotho brought in an average price of US$265.60 (Dh975.57) for stones with an average size of 0.28 carats.

- That gives us a price per carat of Dh3,484.16.

- The faraway planet has about eight times the mass of Earth.

- Earth weighs somewhere in the vicinity of 6 septillion kilograms, so 55 Cancri e tips the scales at about 48 septillion kilos (that's 48 followed by 24 zeroes).

- The new planet is believed to be at least two-thirds diamond, or 32 septillion kilos.

- That's 160 octillion carats.

- At this month's Lesotho price, the diamond planet has a market value of Dh 557.4 nonillion.

Put it this way: if all 7 billion people on Earth were as rich as Bill Gates, who has about $66 billion, it would require 328 billion Earths for us to be able to afford the diamonds of 55 Cancri e.

There is, of course, a catch. On a scorching planet that is chock-full of diamonds, diamonds are not apt to be highly valued. The market would be perpetually oversupplied, and other needs might seem more pressing.

Indeed, it may be that at this very moment the flameproof astronomers of 55 Cancri e are stargazing at a faraway planet that is, to their astonishment, two-thirds coated by the most valuable substance in the universe, a hydrogen-oxygen compound called water.