Madilon was a type of metal that could be used to make hyperdrives smaller in size.
Madilon was a type of naturally-occurring alloy, which had a unique molecular structure that gave it high tensile strength, while retaining a large amount of elasticity. These properties meant that the alloy could withstand the stresses of hyperspace travel, and so it was useful in the construction of hyperdrives. The amount of madilon required for a single hyperdrive was relatively small, but allowed the hyperdrive to be almost ten times smaller in size than one that did not contain madilon. Scientists were unable to develop a method for synthesizing madilon, so the only sources of it were the few planets in the galaxy that contained deposits of it.
Madilon was first discovered in 10,000 BBY and the use of the metal in hyperdrive production was pioneered by the Kumauri Empire. Madilon became a principal component in hyperdrive construction and it allowed starships to make longer jumps when traversing the galactic network of hyperspace beacons but use of the metal was limited, due to the alloy's scarcity.
In 85 BBY, traces of madilon were discovered in rock and soil samples that were taken from the planet Nyriaan. When news of the discovery leaked out, prospectors flooded to Nyriaan in search of madilon. Eventually, a number of madilon mines were established on the planet and Nyriaan became a major exporter of the alloy.