What is the name of the stuff used to etch glass

Question

In art class we made mirrors using glass etching cream and I want to make one for my friend's birthday. I'm sure I can probably get it at Hobby Lobby, but what is it called?

Answer 1

Here are a few Etching Creams I found:

Armour Etch:  

http://www.armourproducts.com/cat--Armou...

EtchAll:

http://www.glassmart.com/etchingcream.as...

Professional 30-Second Etching Cream:  

http://www.glass-etching-kits.com/etchin...