View Larger Image Baltic Brown The mineral composition of Baltic Brown is 55% Potash feldspar, 25% quartz, 11% plagioclase and 9% biotite and hornblende. Kevin McCarthy2019-12-16T18:01:17-05:00 Share This Story, Choose Your Platform! FacebookTwitterRedditLinkedInWhatsAppTumblrPinterestVkEmail About the Author: Kevin McCarthy