When a spell which consumes an expensive material component fails due to counterspell, is the material component consumed?
1\$\begingroup\$ This question actually started as part of my answer to that previous question cited by @Chepelink, but I wasn't comfortable with presuming that everyone who'd voted for that interpretation would necessarily agree with this next step in the reasoning. \$\endgroup\$– SebkhaAug 17, 2016 at 23:36
\$\begingroup\$ Related but not a duplicate: Does a countered spell cost a spell slot? \$\endgroup\$– V2Blast ♦Mar 23, 2020 at 3:41
It seems in line with the idea that a failed spell still consumes a spell slot.
So far as I can tell, as per p. 203 of the PHB,
If a spell states that a material component is consumed by the spell, the caster must provide this component for each casting of the spell.
It seems as though the material is consumed at the time of casting. The spell slot is also consumed at the time of casting, and as it is not returned on the event of failure, I'd think that the material components would not be, either.
3\$\begingroup\$ I agree with this line of thinking. Counterspell is a reaction to a spell that is being cast - the wording of the spell is a bit ambiguous, but saying "the spell fails" says to me that it was actually cast (with all that implies for spell slots and components) but has no effect. \$\endgroup\$ Aug 17, 2016 at 18:27
\$\begingroup\$ @JamesAlday And consuming material components is not an effect of the spell because ...? \$\endgroup\$– Dale MAug 17, 2016 at 21:30
6\$\begingroup\$ It's the cost of casting the spell, not an effect that has a chance to fail. \$\endgroup\$ Aug 17, 2016 at 21:40
1\$\begingroup\$ Exactly - the components are a part of the casting. They are required for the casting to actually happen/work. Imagine buying something - you require a verbal component ("may i have that item?") and a material component (cash). Counterspell doesn't prevent either of those, it just says that after handing over my money I get no item in return. The money is now spent, but it has no effect - like banking fees. \$\endgroup\$ Aug 19, 2016 at 0:26