Cold to fire gem+ orginal sin

do this 30% cold damage as extra fire from gem is converted to chaos to?
how this gem works with orginal sin?

It probably has no affect at all because your damage gets fully converted to chaos damage and you don't have any cold damage to gain the extra damage from.

According to wiki for OS

"

All Elemental Damage Converted to Chaos Damage: This modifier acts as 100% of Fire, Lightning, and Cold Damage converted to Chaos

I think this might work a bit like Avatar of fire but with 100% instead of 50.

When you have over 100% conversion it will split between the conversion types based on the percentages. You can see an example on the wiki for conversion.

So my guess is the cold gets split based on proportions between converting to fire and directly to chaos. Then any fire damage gets converted to chaos.

That would be my guess, not sure for certain, but you can probably check in POB.

As above the result is likely the same, that it all ends up as chaos damage, but the different pathing might mean that you can get some value off say increased fire damage, that you couldn't if it was going direct cold to chaos. Not certain though, may be incorrect.

You gain 30% of your cold damage as extra fire damage. Nothing Original Sin does will change that. They'll both then be converted to chaos damage.

If your skill is doing only cold damage before the conversion, and you have no other sources of extra damage, then you'd be seeing 30% more damage.

Conversion in this game is a one way street. It always follows the order of physical > lightning > cold > fire > chaos. "Gain x% of y damage as extra z damage" is also technically a conversion. Also, skills (both active and support gems) take priority over your gear when it comes to conversion. Last but not least, "elemental damage is converted to chaos damage" in a combination of "fire damage is converted to chaos damage", "cold damage is converted to chaos damage" and "lightning damage is converted to chaos damage".

All that means that in this given example, if we had 100 cold damage, your cold to cold fire would add 30 fire damage and convert 50 to fire. Now you have 50 cold and 80 fire damage. Then Original sin kicks in and converts all of that to chaos, so 130 chaos damage in total.

"

skills (both active and support gems) take priority over your gear when it comes to conversion

Yep so it does work like conversion but what I said was incorrect because I didn't include this? Cold to fire support takes precedence over the ring because it is a skill. So it wont be getting split in this case. Though might be if there are other conversion mods on gear, like say Pyre ring?