One of the most reliable and stable common NC lexemes. The PWC form has a prefixed *ma- of somewhat obscure origin; the labialisation of *c̣ʷ must be explained either by the labialising influence of *m- or by the former oblique base vocalism *-ŭ- (suggested by PL obl. base *c̣ojɨ- / *c̣a(j)-rV-). See Trubetzkoy 1930, 276; Abdokov 1983, 98. Many languages reflect an old oblique base formed with the *-rV suffix (*c̣aj-rV-), cf. PN *c̣ari-, PA *c̣ari- (reflected in Akhv. č̣ari), Lak. *c̣ara-, PL *c̣a(j)-rV-. The same stem with reduplication is probably reflected in PL *c̣arc̣ar 'luster, glitter' (Tab., Lezg. c̣arc̣ar) exactly corresponding to PAT *cǝrǝcǝrǝ 'to glitter' (Abkh. a-cǝrcǝr-ra, Abaz. cǝrcǝr-ra) (with the same loss of glottalisation and absence of labialisation as in *mǝca 'fire').
Another old derivate of the same root is probably PNC *c̣aj-lV 'brilliance, lightning' reflected in PN *stēla (~*sṭ-) ( > Chech. stēla-ʕad 'rainbow', stēla-χäštig 'lightning', /Usl./ stēla 'thunder', Ing. sela-ʕad 'rainbow'), Lak. c̣aj 'brilliance, glitter', PD *c̣ala (Ak. c̣ala 'sparkle', Chir. c̣ala-laIm 'lightning') and PAK *c̣ǝ-wǝ- (with a verbal stem *-wǝ-) 'to shine, glitter' (Ad. Bzhed. c̣ǝ-wǝ-, Kab. c̣ǝ-wǝ-). Note that *-j, having passed to word-medial position in PN, has caused the shift *c̣- > *st- (*sṭ-); note also the absence of labialisation in PAK *c̣ (without the prefixed *mV-).