1) Trigonal mineral 
Sabieite is a mineral with the chemical formula (NH4)Fe3+(SO4)2. Its type locality is Lone Creek Falls cave, Sabie, Pilgrim`s Rest District (Ehlanzeni), Mpumalanga Province, South Africa. Its crystals are trigonal to trapezohedral. It is white and leaves a white streak. It is transparent and has an earthy luster. Sabieite is rated 2 on the Mohs S....