Tyrkal

Tyrkal is a naturally-stable form of nilatite used to generate artificial gravity. It is found in large quantities on the Jiralhanae homeworld of Doisac.

Etymology
The origins for the material's name is believed to be connected to the old Jiralhanae word "Yrrokall", which apparently means "rising rock" or "lifting stone". Over time, the "Yr" sound morphed into "tir/tyr" over generations as different groups mixed together, the word overall got streamlined and lost the "o", while "kall" lost the long consonant as the language became harsher and more crude due to the nuclear winter and tribal warfare. The original word has some similarities with the root name of the species, Yrrolhanag, suggesting some sort of connection between the two.

Today, the most Jiralhanae use "tyrkal" without any regard for or knowledge of the word's etymology. The less developed tribes call them "wonder-stones" or "witching-stones", as they saw a lot of ritual uses during the dark ages.

Tyrkal has a number of alternative names. The UNSC officially calls its Substance-16, but also has referred to it as Exotic Doisac Elements or EDEs.