Mt. Ear, Seward peninsula, Alaska, United States
Nordenskioeldine is a rare tin borate found in alkalic pegmatites and metasomatized carbonate sedimentary rocks. On this specimen are thin platy, colorless to faint yellow grains to 1mm nestled between and in the center of radial groups of muscovite. It exhibits a nicely fluorescent bright yellow color. The black matrix is cassiterite. It is sawed on two sides for EDS work. It is verified by Dr. Igor Pekov.