Does Pyroblast counter a spell that is not blue if it targets a non-blue spell?

Pyroblast has two separate effects: (1) counter target spell if it is blue, or (2) destroy target permanent if it is blue. When you cast Pyroblast targeting a non-blue spell, the spell resolves normally but the instruction to counter it is a conditional that simply cannot be fulfilled — the spell is not blue, so the counter effect does not apply.

Under CR 608.2g, if an effect's condition is not met at the time of resolution (the spell not being blue), that part of the instruction is simply ignored. Pyroblast does not have an unconditional 'counter target spell' clause; the word 'if it's blue' is a restriction built into the single effect, not a separate triggered ability.

This is different from a spell that 'fizzles' due to an illegal target (CR 608.2b). Here the target is legal — any spell on the stack can be targeted by Pyroblast — but when Pyroblast resolves, the condition 'if it's blue' is checked and fails, so nothing happens to the targeted spell.

Example: Your opponent casts Lightning Bolt (a red spell). You cast Pyroblast targeting it. Pyroblast resolves, checks 'is Lightning Bolt blue?' — it is not — so the counter effect is skipped. Lightning Bolt continues to resolve normally and deals 3 damage.

Bottom line: Pyroblast cannot counter a non-blue spell under any circumstances. Its countermagic clause is gated entirely on the target being blue at the time Pyroblast resolves (CR 608.2g).