Rust minimum requirements for Windows assume having at least Windows 8.1 64bit operating system. Your processor should be Intel Core i7-3770 / AMD FX-9590 or a more powerful one. The minimum RAM requirement is 10 GB. As for a graphics card, it should be GTX 670 2GB / AMD R9 280 better. You also have to have 20 GB free disk space to install the game.
If you go for recommended requirements for Rust for Windows, your operating system should be Windows 10 64bit. Recommended CPU would be Intel Core i7-4790k / AMD Ryzen 5 1600 CPU or equivalent. For RAM, it is recommended to have 16 GB or more. And video card — GTX 980 / AMD R9 Fury.
As for Mac OS, Rust requirements here start with OS X El Capitan 10.11 operating system. Processor needs to be at least Intel Core i7-3770 / AMD FX-9590. 10 GB of RAM is required. Your graphics card should be GTX 670 2GB / AMD R9 280 better. Finally, the game needs 25 GB of free disk space.