FWIW: I did check the INTERNAL in Applications/Utilities/DU and that "Get Info" says it is a 500 GB SATA Internal Physical Disk - no further specs on the kind of disk.
What version of MacOS are you using? In either El Capitan (OS X 10.11) or Sierra (MacOS 10.12) the info button in Disk Utility yields a lot more data than you are seeing as you can see in
these screen shots of both an SSD and a Rotating Rust drive.
