This is his discription of the process. None of his AP customers are complaining. Anyway, at less then half of a gen I bought one and I'll take one for the team.
The only thing we do here is the manufacture and double anti-reflective coating of sapphire crystals. We don't deal with mineral crystals and we only offer the best double AR coating available. The sapphire crystals are processed using a proprietary mix of layer materials though a physical vapour deposition process with multiple layers to create maximum destructive interference creating a crystal with reflectivity properties in the visible range of less than .4%. The coating process is done in a laboratory in the United States that primarily performs optical coating for scientific lasers. We have a variety of Audemars and Hublot double AR crystals in stock. We can also provide a service to have your crystals coated with the same coating materials and process, but we can only provide that service when we are sending a large batch for coating, and that is about once every 2 months or so. We can also provide genuine Swiss or German sapphire crystals in certain limited sizes on that same bi-monthly schedule