A custom-cut frequency crystal whose refractive qualities are specifically suited to boosting Mercoxit yield. Due to their molecular make-up and the strength of the modulated miner's beam, these crystals will deteriorate through extended use. Can be loaded into modulated mining lasers only. Type C crystals are used with modulated mining equipment and provide low yields, with very high residues and very low reliability. Typically used for asteroid field clearance purposes only.