Rhydonium was a very unstable fuel source for starships. Due to its high explosivity, the retrieval of this substance was perilous, and its vapors posed a threat to human well-being. It could be located on various planets, including Abafar, Kijimi, Morak, Saracor, and Tralgaria.
"Are you seriously shooting a blaster near rhydonium!?"
When extracted from its container, rhydonium had a visual resemblance to liquid chrome. While it was possible to gather and reclaim it, stringent safety protocols were essential because direct skin contact with rhydonium presented hazards. Breathing in rhydonium fumes had the potential to harm the vocal cords of humans, possibly resulting in muteness. Furthermore, exposure could lead to damage to the brain. Rhydonium possessed a high degree of explosiveness, and the resulting blasts often displayed vibrant colors. However, the explosions triggered by rhydonium extracted close to an Imperial refinery on Morak exhibited only an orange hue. Due to the fuel's unstable characteristics, transporting it on the ground proved challenging, necessitating reduced speeds to prevent agitation and subsequent explosions.
During the age of the High Republic Era, approximately around 231 BBY, the Wyke Town settlement located on Loreth faced an assault from a Greta. This Greta was one member of a mated Gretalax pair, whose Lax had been captured by Layton Wyke, the town's founder, and his followers. During this event, Pela, Wyke's niece, made an attempt to persuade the creature to depart peacefully. However, her uncle instead discharged his weapon at the Greta while it stood near multiple fuel canisters, leading to an explosion that released rhydonium fumes. Pela inhaled these fumes, which had a detrimental effect on her mental state and caused her to lose her voice entirely. Later, when Wyke engaged the services of Ty Yorrick, a monster hunter, to address the Gretalax situation, he attributed the release of rhydonium to the creature, concealing his own involvement in Pela's injuries. Yorrick uncovered the truth during her hunt and revealed it to the settlers. She then reunited the Gretalax pair, after which it healed Pela's injuries that were a result of rhydonium exposure.
The desert planet of Abafar was subjected to extensive mining operations for its rhydonium reserves. However, by the time of the Clone Wars, the resources had been largely depleted. The remaining deposits attracted the attention of the Confederacy of Independent Systems, which initiated the extraction of fuel from a concealed mining installation located near the town of Pons Ora. This fuel was then loaded onto a captured Venator-class Star Destroyer, named the Renown. This was part of a scheme to destroy the Galactic Republic space station known as Valor while it was hosting a strategy conference attended by some of the Republic's most important military strategists.
During the mining operations, the Republic's specialized D-Squad experienced a crash landing on Abafar and inadvertently stumbled upon the plot, initially unaware of the situation. Borkus, the proprietor of a local diner, held the belief that the Separatists were mining rhydonium with the intention of destroying the Renown. D-Squad located and enlisted the assistance of Gregor, a clone commando who had found himself on Abafar suffering from amnesia. Their aim was to bypass the battle droids at the spaceport and escape using a stolen Rho-class transport shuttle. During the escape, the members of D-Squad successfully boarded the shuttle, but Gregor was unable to reach them due to the increasing numbers of enemy droids. He instructed the group to escape and then detonated a massive rhydonium explosion to eliminate the droids. Although Gregor survived the explosion, he sustained permanent injuries, including damage to his vocal cords and brain. After arriving on the Renown, D-Squad uncovered the Separatist plot and confronted Separatist droids while attempting to devise a way to thwart it. As the rest of the team evacuated the Renown upon its arrival in the Carida system, the astromech droid R2-D2 prematurely detonated the flying bomb, averting the destruction of Valor. Despite being destroyed in the process, R2's remains were recovered, and he underwent a complete reconstruction.
By 9 BBY, Jabba the Hutt had initiated rhydonium mining operations on Abafar, Saracor, and Tralgaria.
Fourteen years following the conclusion of the Clone Wars, rhydonium was discovered within Fort Anaxes, a former Republic base that had transitioned into a smuggling outpost. During a supply acquisition mission, rebels Sabine Wren and Hera Syndulla utilized the remaining rhydonium canisters to eliminate fyrnocks that were endangering them. Damage to the VCX-series auxiliary starfighter Phantom had left them stranded at the base during an eclipse, and the resulting darkness had allowed the voracious creatures to launch an attack.
In 3 ABY, a rhydonium consignment was dispatched to Fuel Station Visavi while it was positioned in orbit around the Outer Rim Territories moon Toshara. Following an initial refusal, Queen Ashiga of the Ashiga Clan entered into a trade agreement with the Galactic Empire, granting them access to rhydonium extracted from the mines of Kijimi.
Rhydonium persisted as a starship fuel source up to the time of the Battle of Jakku. The wreckage of ships scattered across the surface of Jakku released rhydonium and other fuels, rendering the sands perilous for scavenging. Nevertheless, scavengers persisted in their search for this valuable fuel.