The law increasingly treats copyright as if it were any other form of property, and numerous writers decry this trend. In particular, scholars who express solicitude for the public domain fear that the "propertization" of copyright threatens an inevitable accretion of private rights in information at the expense of the public domain. This Article questions this conventional view, arguing that the propertization of copyright has unappreciated advantages for users of public information. The conventional view relies on an overly narrow view of what propertization means. The treatment of copyright as a form of property generally entails not only reduction of entitlements to private ownership, but also the bounding of those entitlements with clearly demarcated, or "crystalline" borders. Although many writers prefer "muddy" entitlements that create fluidity regarding the extent of the public domain, this Article argues instead that it is this very fluidity that is at fault for excessive accretion of private rights in information. Uncertainty about the extent of public entitlements in information allows well-capitalized private actors to lay claim to resources whose public/private status is at all ambiguous, and then deter the public's claims through threats of litigation. By contrast, a public domain characterized by crystalline rule structures would benefit users, as well as owners, by allowing them to better comprehend the extent of their entitlements and thus to exploit common resources without fear of suit. Three examples illustrate how copyright law could be reformed to create user-friendly crystalline entitlement structures. The Article concludes by situating the propertization of copyright law, and this critique of the dominant narrative of that trend, in the context of current debates in property law.