the rune is a great idea, but it looks like you used a brush. You also see the brush storkes on the forehead detail. While some people can do that with a brush (I haven't met any) I find that using a technical ink pen (like Rapidograph) with a colored ink makes a cleaner line. Just make sure you keep it clean, and store it twith the tip up. I'm jealous of those gems - I wish I could get them to look that brilliant.
Very nice pic, but there are some things that keep me from voting this mini higher. First you should try to thin your paints. Second you should try to highlight the runic armour. Third you yhould try to thin out the rune on from of the cloak. Keep up the good work though!