Itsiite is a new barium calc-silicate found at the Gun Claims in the Itsy Mountains of the Yukon Territy. Approved by the IMA in 2013 (IMA 2013-085), it was studied and authored by Anthony R. Kampf, Ronald C. Peterson und Brian R. Joy CNMNC Newsletter No. 18, December 2013, page 3255; Mineralogical Magazine, 77, 3249-3258. It occurs as blue platy crystals.