Scales is a Tertiary gene. You can get it through Baldwin's Bubbling Brew if you are a Level 7 in alchemy.
To make it you need: 3 Silver Mucks, 2 Black Slimes, 6 Yellow Sludges, 7 Green Goos, 1 Glass Beaker, and 100000 Treasure.
The gene takes 11 hours and 50 minutes. It rewards you with 1650 XP.
I am a little put off by the name as dragons should always have scales. Well...the ones on Flight Rising at least.
The gene can be hidden by certain colors and does have a good look to it. I'm now half-way tempted to get the gene for my AlexanderIsaacs as it does look beyond awesome on him.
If you have any examples of dragons that work or don't work with Scales please post them in the comments. I might do something with them later.