I need help identifying this one...

Are you in Virginia? Looks like Actinolite or kyanite because the blue ones are unique.
It isn't tourmaline because you say they are "cubic"

Northern Canada over here - Was thinking maybe Arsenopyrite, but haven't found anything that really matched up online. The blues/iridescent colors you see is possibly just from the light shining on the objects. To the naked eye, these look like rods of silvery metal.

It looks like some type of pyrite embedded in a quartz matrix. Perhaps they were formed by inclusion rather than crystallization which might have resulted in the tetragonal shape? That's just a guess.

prhaps if you took a closer shot at the metallic rods. and put a coin in the picture for some scale.
Its a quartzite mass so the metallic stuff could be n iron mineral that has that habit of long rodas. No pyritic rocks (arseno, cupro, ) take that extreme rod form.
Is it magnetic?
if you take a crystal chunk and hold it in a flame does it have any particular odor?

Theres quite a few of the Nickel iron sulfides (Loellinghite, millwerite) that form long shards like those.
A real find would be if its stibnite (which often forms in qurtz veins as you have there).
Stibnite is the primary ore of antimony so don't go licking it.

The average length of these rods are around 2 mm in length. I zoomed into this specimen with my DinoLite - Non-Metallic

Sylvanite?