Were Kelsh and Meleenium made up by James Luceno?

Question

In the final book of the New Jedi Order series, we have the following passage:

Coruscant, Nom Anor thought ruefully.

He had never been comfortable calling it Yuuzhan'tar - except, of course, when necessary. Shimrra's shapers might have fashioned a leafy ooglith cloaker for the planet, but scratch the surface and you found ferrocrete, transparisteel, kelsh, and meleenium - the foundations and skeletons of once-robust edifices and the corpses of thousands of droids.

This is the first time I've ever heard of the materials "kelsh" or "meleenium", and neither one has any real history in the EU according to Wookieepedia.

Were these two materials made up by the author (James Luceno), or had they appeared previously in Legends canon?

Answer 1

Meleenium

This substance makes its first appearance in Galaxy Guide 4: Aliens Races, originally published by West End Games in 1989.

Trade and Technology:

Because of the tremendous velocity needed to escape from the gravity well of Af'El, the planet is seldom visited. However, as it is the only known source of naturally occurring meleenium (trace amounts of which are used in durasteel and its associated alloys), Vulca Minerals, a mining corporation, does send a freighter to the planet once each standard year, exchanging a large shipment of fresh foodstuffs for a significantly smaller amount of meleenium.

_{^{Galaxy Guide 4: Alien Races - Defel}}

It's mentioned in the new (canon) Catalyst novel, making it part of the official Star Wars universe.

What I learned when I was hired, the sea has some large areas of polymetallic nodules in the active hydrothermal vents. The vents create deposits that contain ores like doonium, meleenium, dolovite, kammris. T/B uses hydraulic pumps to bring ores to the surface to be processed. The tailings are collected and sent to offworld cleansing centers.

_{^{Catalyst: A Rogue One Novel}}

Kelsh

This substance first appears in an earlier source, Shaara and the Sarlacc: The Skiff Guard's Tale from January 1996.

When she opens the door, still wrapped up neatly in bronze-colored kelsh metal, she sees them removing their armor and going through her things, so she wisely makes like the Kandos shuttle and departs ahead of schedule. They follow her. Why should they not follow her? They are after all the law, and nobody is going to interfere with them.

_{^{Shaara and the Sarlacc: The Skiff Guard's Tale}}