I discovered using an elemental staff also increases your level of protection. This is in addition to the Barspell, but is only vaild while you are equiping the staff. I saw a 20 point increase when using the HQ staff over no staff. (I was testing at level 75.)
The spell increases your earth defense by about 40. I'm not sure if or how much it goes up as your enhancing skill goes up, lasts about 1 minute, give or take.
I probably got the one in a blue moon drop, but this one dropped for me, so I didn't have to pay anything. I just have to find out what this spell does now. It does drop, I think I got it from one of the bird men in Sarutabaruta.
Look under scrolls in the auction house and the spells will be there for sale...I regret to say that they are pricey like anything else in the ah. The official site should start making a price list for items to stop the high pricing in the ah. We are talking 1000gil+ for each of these in San D'Oria where my rdm is. This is pretty expensive for 5th to 7th level. But anyway this is where you can get them until I find out where the quest point is anyway.
increase target's resistance to stone? maybe it seems that all the barspells increase the target's resistance to whatever the "spell" is. it makes sense to me...but i could be totally off.