Quartz is an AI-native email client for macOS that auto-categorizes every message by importance you define and learns over time, so important mail gets room while FYI, Icebox, and Noise collapse out of the way. It drafts replies that sound like you by learning your writing style, your relationship with the sender, and the context of each thread. Crucially, the model that sorts the inbox and writes drafts runs locally on Apple Silicon, so mail is never uploaded and stays encrypted on-device with keys only the user holds. Quartz connects to Gmail and has been independently audited under Google's Cloud Application Security Assessment. It is currently available as a public beta download for Mac.