Help! External hard drive has become invisible.

Mid 2012 rMBP + LaCie Minimus external drive.

I've used this drive with no issues for 2 years (it is now 3 weeks out of warranty). Starting this morning it is invisible to the mac. I unmounted and disconnected the drive last night. Did my normal routine this morning and it is nowhere to be found.

The drive appears to be acting normally. When I connect it to the computer it starts up, the blue led remains lit, and I can hear the disc spinning. Just as always. However, it does not appear in finder or disc utility. The only place I can see it is when I run a system report.

I've looked everywhere for a solution. I've also unplugged it and let it sit, and shut down the mac with it connected. Nothing.

Please help! Any suggestions are appreciated.

Thank you guys for the help.

I don't have another cable, however I did try another USB port. Same.

I also plugged it into a windows machine. It started to install the device driver, failed, and could not be "seen" anywhere on that machine.

Finally, I bought a drive enclosure tonight, thinking I could check for a cable or controller card issue. Same behavior. It will spin up and continue to spin. But it cannot be seen anywhere on the Mac or the windows machine.

Is it safe to say the drive is toast?

I do have a 2nd backup of the data on another drive at my office. I haven't backed that up in a couple of months, but it could have been much worse.