Iridonia, the homeworld of the Zabrak race, is a rocky and inhospitable world of pale, razor-sharp limestone ridges, deep valleys, and dust. Perhaps long ago, an ocean covered the whole planet, as the fossils of fish and aquatic invertebrates abound in the chalky surface strata, but most of that water is long gone, leaving behind a dry karst landscape, full of potholes and crevices into which the infrequent rains disappear as if into a sponge. Vast areas of the planet have no surface water at all, making the transportation of water crucial to the many small settlements that dot the broken landscape. Large areas of the planet are also rendered uninhabitable due to volcanic activity. Indeed, Iridonia is home to one of the largest volcanoes for parsecs around - the mighty Mount Merapi, which sports a lava lake almost five kilometres across, atop a cone that reaches over six thousand metres in height. The base of the volcano is over one hundred kilometres in diameter. At night, the glow from the lava lake lights up the sky as brightly as a late sunset.

Most of Iridonia's population is centred around its sunken seas. The planet's three small oceans sit an average of three hundred metres below the level of the dusty surface, in great depressions scooped out of the limestone by the actions of wind and water, and fed by water seeping through the porous rock surrounding the seas. The salinity level of the water is over forty thousand parts per million, making the water unsafe to drink without thorough desalination and purification. This combination of inhospitable landscapes and scarce drinking water means that life on Iridonia is harsh, even if the planet's other physical characteristics do support life. The local flora and fauna, like the native Zabrak themselves, are hardy and robust, with strong outer skins and features to minimize water loss, including waxy leaves, thornlike leaves, minimal sweat glands, and the like.

Iridonia has long been a link between the Inner and Outer Rim, sitting as it does in the Mid Rim near many hyperspace trade routes. The Zabrak themselves were among the races to independently discover hyperspace travel and their homeworld has been historically significant for millennia. Several important battles took place around the planet during the Old Sith Wars and the planet itself fell to the Neo-Crusaders during the Mandalorian War. It changed hands several times during the Jedi Civil War and even hosted a Sith Academy around one thousand years BCGT.