Is this a pest spider mite
 

Or a benefitial garden spider?

I'm not seeing it... but if it is big enough to see, it's a spider.(good) Spider mites (bad) are so tiny, you need a hand lens to see them as any more than dots. And there's never just one.

Thanks. Yes I can definitely see it.

In the center of the purple circle.

You need a very strong magnifying glass or microscope to see spider mites. You can see the webs they weave as very fine silvery sheen, usually on the undersides of Phal leaves. On thin-leaved orchids (and other plants) they progress from webs under the leaves to webs encasing the whole leaf. They're mainly active when temperatures are warm and humidity low. When the humidity is over about 80% they are uncommon.

Definitely not a spider mite. (at least a hundred times too big) Can't see it clearly, but just a tiny spider or something.