G stands for Glass Paint.
C stands for Ceramic Paint.

Do note that colour will differ slightly due to lighting issues.
 
Ceramic Paint (C)
Per bottle: 20ml
Colours:
#1 Lemon Yellow , #3 Orange, #4 Crimson,
#5 Ruby Pink, #6 Parma Violet, #7 China Blue,
#8 Creamy Blue, #9 Turquoise, #11 Olive Green,
#12 Leaf Green, #13 Chocolate, #14 Cotton White
#16 Gold, #18 Varnish
Ceramic Outliner - Silver
 
Glass Paint (G)
Per bottle: 20ml
Colours:
#2 Saffron Yellow, #3 Tangerine, #4 Garnet Red,
#5 Amethyst, #6 Purple Pink, #7 Rose Pink,
#11 Aniseed Green, #12 Bamboo Green, 
#14 Amber Brown, #15 White, #16 Black
Glass Outliner - Silver/Gold