Clear Mirror Glass - 3mm thick
Modern mirror can be made by silvering. Spraying onto the back of float glass, a thin layer of silver or aluminum. Process was invented in 1835. Now, most mirrors are made by heating aluminum in a vacuum, which then bonds to the cooler float glass. Two layers of waterproof paint are applied as back-side protection. The thickness is the same as art glass. Surface is flat, smooth and reflective.
Note: Protect mirror edges from deterioration if exposed to chemicals like flux or patina