elemental burst clarification

[Ectar]

Johnny McNostrength swings his +1 flaming burst scimitar and hits on a 17.
He deals 1d6+1d6 damage.

Next round, Johnny gets a nat 20, with successful confirmation roll.
Does he deal 1d6+1d6+1d0 or 1d6+1d10?
I had always thought it was the latter, but rereading the ability makes me think the former.

[Java Man]

Nothing about the weapon enchantment changes the basic rules of the crit. So your example would be 2d6+2 (scimitar doubled) +d6 (flaming) +d10 (flaming burst).

[Ectar]

Mostly I was just questioning if the 1d6 fire damage was overwritten by the 1d10 fire damage or if you get both on a crit. Thanks!