High-tech sensors on board probe the arid sands below, looking for buried diamonds.
This is De Beers' latest tool in its search for gems in Botswana, the world's leading diamond producer by value.
The rigid dirigible with a disaster-scarred history carries classified US technology, first developed for the military and still so sensitive that a photographer was warned not to film the equipment, provided and operated by US firm Bell Geospace.
"This is the cutting edge. We're pushing geophysics to the boundaries," said Brad Pitts, who heads De Beers' airship exploration programme.
"This is the only airship in the world being used for geophysical surveying."
The zeppelin, which has a metal frame unlike the non-rigid blimps, costs about 7 million euros (£4.8 million), but De Beers has leased this one.
As the airship floats 80 metres (262 ft) above the desert, the equipment pinpoints rock formations with lower density --where "kimberlite pipes" with diamonds may be found.
Botswana's most obvious deposits of diamonds, where gems were thrust close to the surface, have already been uncovered and De Beers' joint venture with the government - Debswana - is under heavy pressure to find new deposits.
"It's a big challenge facing all diamond exploration. We are now looking to discover the tougher ones," Mr Pitts said.
Existing mines are yielding lower-grade ore with fewer diamonds, forcing workers to drill deeper.
Miners are increasingly tapping science to help uncover diamonds buried hundreds of kilometres below the surface.
Miners hunting for elusive diamonds seek traces of the volcanic rock that forged the gems millions of years ago.
The huge Jwaneng open pit mine, about 200 km (120 miles) west of the capital Gaborone, was discovered after termites looking for water brought to the surface mineral grains from the massive diamond deposit, one of the world's richest.The zeppelin is part of this process.
The system on board the airship has also been used on small aeroplanes, but vibrations caused false readings, while using it on the ground limits the area covered.
Mr Pitts said: "A ground crew can cover five km a day while the airship can do 250-300 km," he said.
The airship takes off at sunset and flies for six to seven hours a night because there is less turbulence then.
Before the airship operations started around Jwaneng, De Beers officials met with chiefs in the surrounding remote areas to brief them about the strange floating oval in the sky.
The venture could mark a comeback for Germany's Zeppelin company, founded by Count Ferdinand von Zeppelin eight years after he flew the first zeppelin airship in 1900.
Zeppelins enjoyed a golden age in the 1930s when they carried passengers on hundreds of trans-Atlantic flights.
But they fell into disrepute after the spectacular 1937 Hindenburg disaster, when an airship burst into flames in Lakehurst, New Jersey, killing 35 people on board.
The Zeppelin company lived on, however, and the ZF Group became a leading supplier of car parts such as chassis.
In 1997, a subsidiary launched New Technology Zeppelins, which have mainly been used for tourist or promotional flights.
"This (De Beers airship) might mean zeppelins could be used for other commercial applications," said pilot Fritz Guenther as he steered the ship above Jwaneng, waving at curious people below.
Mr Guenther is part of a German team from the Zeppelin company operating the ship, which is filled with helium and has propellers on
the sides, allowing it to take off vertically like a helicopter.
Bostwana is De Beers' key producer, providing 32 million carats of diamonds last year, two-thirds of the total for the company which is 45 per cent owned by mining group Anglo American.
De Beers - which controls around half the world's diamond supply - is scrambling to find new mines after a European Union anti-monopoly deal will force it to stop distributing diamonds from Russia's Alrosa from 2009.
Besides spending around £4.6 million on airship exploration this year, De Beers is also using equipment that measures the ground for magnetic forces and electrical conductivity to unearth new deposits.
After pouring over the data, it sends out ground teams to drill down under the desert sands. Finding a concealed volcanic "kimberlite pipe", though, is no guarantee of success.
Only one in ten kimberlites typically contain diamonds.
Mr Pitts says the zeppelin has technically proved itself during a few months of test flights, surveying ground over which geological data had already been collected.
But when asked whether the project had resulted in any big discoveries, he chuckled: "If I told you, I'd have to shoot you." ..SUPL:
