Caesium Iodide is grown by sealed ampoule Stockbarger techniques with ingots of approximately 70mm diameter. CsI is very soft and pliable. IUPAC International Union of Pure and applied Chemistry recommends the spelling as Cesium. UK Useage is Caesium.
REFERENCES:
(1) Handbook Optical Constants, ed Palik, V2, ISBN 0-12-544422-2
(2) Rodney, J.Opt.Soc.Am. V45, p987, 1955
(3) Combes et al, J.Opt.Soc.Am. V41, p215, 1951
(4) Kelly, Bureau of Mines Bulletin, No371, p51, 1934