Are ore color locations always the same?

[Daltrey]

Once a colored ore location is discovered, is the vein always that color (i.e. making it worthwhile to mark it)?

Also, does the location always yield a similar amount of ore?

Or, are both of these random on this shard?

[Silverfoot]

The vein is always that color and yields a similar amount of ore.

[Daltrey]

Thank you!