Some of these coatings are hard to find out about . AFAIK ,The Glock and Melonite are similar but the procees of making it may be different .
Gun coatings first started out with carbonitriding ,some done with gas which puts a thin carbon+ nitrogen rich layer on the gun .This is very wear resistant but rusts fairly easily. Later this was modified to oxidize the surface [IIRC !!] which adds considerable corrosion resistance .It is then blued.
The result is an extremely durable finish !!