Jacquard Pearl-ex mica pigments
Is the proper name, they are the ones that are used for scrapbooking, clay work, etc. Any better arts supply stores will have something other than the sets. Blick's
is one that has both the sets and bottles of each color along with numerous other pigments.
They were used in pin stripping and sign painting to give a kick to line work or letters. It was blown on to the wet paint. It could drive another painter crazy trying how to achieve the effect. If they didn't know the secret