A rare Tre Skilling Green is still available on the collectors market following AB Philea's philatelic auction in Sweden, yesterday (February 17).

The stamp was to sell with a reserve price of 12,000 Swedish Krona (about $1,600).

Although the Tre Skilling Green is a rare stamp in its own right, by far its most remarkable quality is its relation to another stamp which needs no introduction among philatelists...

Tre Skilling Green (Click to enlarge)

The Tre Skilling Yellow has been described as the most precious item in the world. According to the Guinness Book of World Records, it is also the most valuable object of any type by weight, volume and density.

The Tre Skilling Yellow is the 'most precious item in the world', with an estimated value of $2.33m

Originally discovered by a schoolboy, the Yellow version of the usual turquoise-green Tre Skilling is understood to have resulted from a printing error.

Since first going to market in 1885, the Tre Skilling Yellow has belonged successively to many of the world's top collectors.

Today, the stamp's worth is estimated at an incredible $2.33m.

Its relative, the Tre Skilling Green, failed to find a buyer at AB Philea's sale.

But all is not lost: unsold lots will continue to sell until AB Philea's next sale, which is scheduled for March 17.