Manufacturers want their product to be accepted for what it is, rather than a vehicle for defrauding others. If someone bought a manufactured stone expecting i

Manufacturers want their product to be accepted for what it is, rather than a vehicle for defrauding others. If someone bought a manufactured stone expecting it to have been mined (and paid the premium currently accorded to mined stones), the buyer might direct a fraction of their disappointment at the manufacturer, instead of the deserving fraudulent seller. Adding a nigh-invisible mark makes it trivial for a jeweler to tell the difference, and stops all but the least-informed fraudulent sellers before they begin.