If you do a
You'll get something like
Serial-ATA: Intel 6 Series Chipset: Vendor: Intel Product: 6 Series Chipset Link Speed: 6 Gigabit Negotiated Link Speed: 3 Gigabit Description: AHCI Version 1.30 Supported APPLE SSD SM256C: Capacity: 251 GB (251,000,193,024 bytes) Model: APPLE SSD SM256C Revision: AXM09A1Q Serial Number: S0TNNYABB29779 Native Command Queuing: Yes Queue Depth: 32 Removable Media: No Detachable Drive: No BSD Name: disk0 Medium Type: Solid State TRIM Support: Yes Partition Map Type: GPT (GUID Partition Table) S.M.A.R.T. status: Verified Volumes: disk0s1: Capacity: 209.7 MB (209,715,200 bytes) BSD Name: disk0s1 Content: EFI Macintosh HD: Capacity: 250.14 GB (250,140,434,432 bytes) Available: 196.49 GB (196,489,560,064 bytes) Writable: Yes File System: Journaled HFS+ BSD Name: disk0s2 Mount Point: / Content: Apple_HFS Volume UUID: 065EFF5F-A718-38F6-8C8E-9928E93FBD0E Recovery HD: Capacity: 650 MB (650,002,432 bytes) BSD Name: disk0s3 Content: Apple_Boot Volume UUID: 3D372E6C-4795-3400-8878-327807A098C9
That "Medium Type" is what you're after. If it's SSD it will be "Solid State" if it's spinning disk it'll be "Rotational"
However, I don't know how this holds for third party SSDs. This is with an Apple-supplied SSD (MacBook Air).
Work up an EA from those results.