So I just fiddled around in Mids and realized something I had completely forgotten: with my slotting Fault is permanent so that throws Earth Mastery right out since Stalagmites would be overkill. That brings my choices to Ice and Fire. I'm leaning toward Fire for a little bit of AoE damage I think. So I suppose I've answered my own question. 
Funny how that works out.
How's your endurance? I've found mine a problem but then he's still running on SOs. If you're playing at higher reps then it'd be an idea to take energy mastery for the +end and +recovery from Superior Conditioning and Physical Perfection. Otherwise, the extra AoE from Fire would be a great addition to Stone's impressive ST output
I am the Blaster, I have filled the role of Tank, Controller and Defender
Sometimes all at once.
Union EU player! Pip pip, tally ho, top hats and tea etc etc
No endurance problems at all actually. The only time I can even get the end bar moving substantially is on very large and/or drawn out fights. So it's looking like I'll probably go with Pyre Mastery. Yay for Fireball.
Soul Mastery for Darkest Night. That'll stack well with RttC's ToHit debuff.
My guides:Dark Melee/Dark Armor/Soul Mastery, Illusion Control/Kinetics/Primal Forces Mastery, Electric Armor
"Dark Armor is a complete waste as a tanking set."
Soul mastery is total win. i ran with mu on my own stone/wp first for the extra aoe dmg but then respecced for soul to see the difference and WOW...my survivability went higher than i ever would have thought. just the other day i did the ice mistral sf and mowed through the entire ambush archus spawns. while the rest of my team(an invuln tank included) eventually died i kept killin till the entire army was dead and the rest of he team was speechless
@Injenius~Virtue
Stonefather - 50 Stone/WP/Soul brute
Sable Affliction - Earth/Dark/Fire Dom
Wild Cipher - Beast/Time MM
I've recently picked my Stone/WP Brute back up after a long hiatus away from him. I tried out Scrappers for a while and well, it made me realize I just prefer Brutes.
Anyway, I'm working up a build for him (up until now he's had Common IO's only). I'm focusing on Max Health and Regeneration, and pretty much have the build to a point I like except for one thing: I can't really decide on an ancillary pool (the character recently side-switched to hero and I'm unwilling to side switch him again to get a Patron pool).
So of the ones available I'm looking at Pyre Mastery to give me a little bit of AoE, or possibly at Earth Mastery for yet more control. What do you guys think? I had thought about Energy Mastery, but honestly with his build I see Physical Perfection as more or less overkill. He's got 670% regeneration without it (and that is only counting 1 mob in RTTC range) and 4.12 end/sec recovery.
Any ideas? The character is half way through 40 and I'd like to avoid a respec by making a choice of Ancillary I won't regret later. I guess I just need some convincing as to what would work better with his setup and was hoping the Brute community could help.