Opalescence is a sheer while with pink and blue (wait for it) opalescent shimmer. Shimmering Star is pink with pink gold shimmer. The photo below shoes one "shake" from the bottle on my forearm, Shimmering Star on top and Opalescence below.
This shows the two powders spread onto the skin but not blended out at all in shade:
Unblended in full sun:
Blended in full sun:
You can see how subtle they can be - or how impactful, depending how you use them. They stand out even more over primer or applied wet. I have used Shimmering Star alone and as a cheek highlight. Opalescent could be used either way, but I prefer it as an eye highlight.