Energy rune I can't use ?

My Ranger/Elemental has an 'Elemental rune of minor energy storage', but I can't seem to use it. It won't add to my armor or weapons. Are runes for primary skills only ?
Thanks,
Dr Wu

Runes are only applicable to your primary class.

You can't use that specific rune because you chose Elementalist as your Secondary profession and thus you don't have the Energy Storage attribute. That attribute is a the primary attribute for an Elementalist.

Doh!......I bought a Rune of Blood magick (minor) for my R/n.....no good i guess

No good for that character anyway - throw it in storage if you ever plan on making a necro.

Sell it