After my earlier post comparing a Barry M Glitter and a Nails Inc Glitter I went digging through my glitters looking to see if I have any other dupes.
The comparison I am making now is between Barry M Rose Quartz Glitter and OPI Servin Up Sparkle will never be an exact dupe as there is an obvious colour difference.
Both are made up of small glitter with larger hex's and both have holographic sparkles.
My starting point for this mani is 2x Nail Envy 1x Matte Magic then 2x Nails Inc Southwark.
I then used OPI on my right hand with an accent nail of Barry M for comparison, and reversed this on my left hand.
Ironically these two glitters have opposing problems, the OPI will provide a good coverage of the microglitter and I have to fish about to get the larger hexs. The Barry M gives lots of large hexs and virtually no smaller ones.
In some lights there is no difference at all in the two colourwise, in others it's more obvious.
I would say that unless you're an absolute glitter nut like Jazz at GlitterInfatuation you probably don't need both, I had already got the OPI when I went mad and ordered a load of the Barry M ones directly from their website on day of release rather than waiting to see swatches. My personal preference is the OPI as I would sooner get a good even layer of small sparkles with a scatter of larger glitters than a sparse covering.