Runes

A rune is a container that holds an array of thaumite orbs connected with metal logic components, otherwise called a spell. Runes are used to quickly change out spells in spellcasting devices designed specifically to use runes.

Invention and First Application

A Eurekan wizard in the early years of the Third Era discovered that, when placed in a conductive cartridge and housed safely into a spell casting device, the spell worked as normal, and could be safely and nearly effortlessly removed from the device. She first tested this by creating a small amount of water by using a simple spell configuration, and successfully used a spell to remove the water again after replacing the rune.

Utility

Runes became incredibly useful in wands and staves manufactured in the Third Era, allowing soldiers to quickly replace drained spells with new ones whilst their old ones recharged. They weren't super useful in household appliances or other, more recent inventions, however, since it was simply easier to build an array into the appliance itself instead of having changing parts.

It did prove useful to certain manufacturers, however, as a light fixture could now easily have more colour settings, for example. Appliances could now be sold for more up front with the benefit of runes being cheaper to manufacture and replace than the appliances themselves.

Manufacturing

Apprentice wizards can find jobs in manufacturing quite easily, doing mind-numbing labour by putting together orbs and logic components into the right places. Wizards in the Third Era often start off doing this kind of manufacturing to earn enough money to live off of and save up for higher level competency exams.

Availability

Runes, while fairly uncommon sights to see in Keiman City, are incredibly expensive. Runes are several hundred rounds just for a basic spell, and only go up in price. Eurekan government also demands anyone buying runes must be a wizard, have a military license, or be buying a specially shaped rune specifically designed for civilian appliances.

Complexity

While many aren't overly complex in design, magic and spell creation is kept a mystery to the populace, and runes are sold enclosed in a way people cannot tamper with them.