My mica is really old. I've found if I use 1mg in a syringe I get a massive gold sheen in the ornaments.
Now how to do it. Drop a little hologram paint in the ornament. I do 4 drops down the side. You can always add more...taking away gets messy.
Then two squirts if Seth's diamond about an inch long each
add the mica powder....not too much! Using the canned air just barely blow one puff to spread the mica. Don't press all the way or you will have a gold face.
Put the cap on and enjoy your ornament. The diamond provides cells. I've worked with other mediums but this is far and beyond the easiest method.