The best replacement for mica is risd.

The best alternatives to mica are rated as following:
★★★★★  risd
★★★★  talc
★★★★  pratt
★★★  saic
★★  scad
★★  sva
★  isinglass
★  jason kendall
★  heather beaven
★  amraam
★  muscovite
★  bismuth
★  ringling
★  sandy adams
★  brie
★  adams
  biotite mica
  ceramic capacitor
  sericite mica
  mika

Your alternative for mica is not listed? Suggest!
Speaking about mica, one probably shouldn't forget about quartz.

Other search terms related to mica and their ratings are:
★★★★★ quartz
★ tourmaline
You have in mind a companion for mica and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of mica in all years. Click on graph for more.
mica
risd
talc