Stardust

Common name for a variety of powders composed of finely ground crystalline materials infused with magic, such that they produce twinkling light. The key defining feature of stardust is its neutral magical charge- the process of infusing it with magic is set up to explicitly divest Celestial ownership from the source, resulting in a high magical charge without the typical consequent claim. As a result, the material must be stored in specially enchanted containers (typically etched glass vials) and ideally worked in specially enchanted rooms to avoid contamination. This process also gives the material its distinctive twinkling shine.
Compositions vary. White stardust, the cheapest variant, is composed mostly of quartz and ignium, with a very small (<2%) amount of diamond, retaining relatively little energy. Gem stardust is composed of a ground gem- typically emerald, sapphire, or ruby, diamond, and ignium. It is an order of magnitude more expensive and effective.
Stardust sees use in hard light circuitry, typically to act as a capacitor, as it handles the intake/output of magical energy much more rapidly and efficiently than raw ignium. Good stardust is more efficient than orichalcum, but an order of magnitude more expensive.

History

Stardust was first created by mages, centuries prior to the rise of enchanting as a field. Early stardust had neither the lack of Celestial ownership nor the extremely fine particle sizes now associated with it. Neither properties were as important in arcanism as they are in enchanting.
Its use to mages is in the creation of implements. Previously, ground gem dust was used as a filler material for implement cores, and the richest could afford to use massive, solid gemstones. Stardust provided a way to attain levels of implement efficiency reminiscent of gemstones while being slightly more affordable and offering far more flexibility in size and shape.