Ha Ha, it's not even glass. Best get a screen protector, I am using a cut now smart phone one. But there are plenty of custom ones on ebay.
Over the years I have used Zagg protectors on all my Garmins (old yeller etrex,foretrex 101,Legend,60csx,and various NUVIs) BUT, they don't now have one for my etrex 30 and after many contacts (phone email etc) with the company,they don't seem to have plans or any interest in making one available. They suggested I buy one of their universal kits, which they don't sell themselves, but farm them out to Nebraska Furniture Mart, Amazon, Toys R Us at an outrageous price considering you have to cut them out yourself and they are not covered by their lifetime warranty. So after searching around and using some low quality protectors available at Target, Walmart etc I finally found "XO Skins" website carries them, very similar in quality to Zagg,crystal clear, same installation involved not as pronounced "orange peel" finish as Zagg, and oh yes, LIFETIME WARRANTY!!!
Problem solved... xoskins.com/gps-skin-protectors/garmin-skin-protectors/ga`rmin-etrex-30-screen-protector
See ya'