4 U ni qu e Prop er t ie s S il v ery white o r gr a y in co l o u r t h e se m e tals ha v e a hi g h lustre a n d t arn ish r eadi l y when e xp o sed to air REEs ar e f o u n d in m o st e v e ry d ay ap p li ca tio n s b ecause o f t h eir un iq u e che m ical a n d ph y sical pro p ertie s N ew ap p li cati o n s h a v e ari s en co n si s te n tl y o v er the pa st 5 0 y ears CIBC in clu d in g i m p o r tant env iron m en tal in n o v ati o n s such as ca taly tic c o n v erte r s an d the de v el o p m ent o f p erm an ent m ag n et s which hav e enab l e d g r eat e r e ffi cienc y m in iatu riz ati o n du rab il ity and spe ed in el ect ric an d elec tro n ic co m p o n en ts Su b stitut es e xist b u t ra rely w o rk a s e ff e ctiv el y Th e p ro p ertie s o f e ach RE E al o n g with t h e p erce n tage share o f est i m a te d gl o b al p r o d u cti o n in 2 0 1 5 ar e su m m ari z ed in t h e f o ll o wing t ab le REE Cata ly tic Ma gn e tic E le ctrical Chem i cal Op tical Sh ar e o f E s ti m at e d Wo rld Su p p ly in 2 015 L an than u m L a x x x x 27 Ceriu m Ce x x x x 40 P rase o d y m iu m P r x x x x 5 N eo d y m iu m N d x x x x 16 Sa m ari u m S m x 2 Eur o p iu m Eu x 4 Gad o li n iu m Gd x x 2 Te rb iu m T b x x 2