I'd observe my skins reactions to different mineral mixes, try samples first. Not all minerals have the same hardness or sharp edges when reduced to a base powder form the way mica has.
Mica's made up of a a few different minerals but silicate is a large component, which is what sand is and when sand is melted down forms glass.
There are some minerals that are soft, for example graphite and it won't scratch you no matter what you do with it... so there very well may be a mix that won't hurt your rosacea, or a company that mills and tumbles their powder to silky perfection!!
I'm sorry but I do not have extensive knowledge on other minerals at this point... I'm aware of mica because it has become the most common offender for me in skin care.
If you've got a geologist friend have them read the mineral powder ingredients they can probably tell you which when milled might still retain jagged edges and cause abrasions on sensitive skin.
Mica's natural structure is sheet-like and can be easily separated into little leaflets. I suspect when it is milled it still breaks in a way that doesn't betray it's natural mineral structure so it could scratch. It' really pretty though!!
/emoticons/
