Rasendracudamani 11.2

11.2

{sulfur:: subtypes}
caturdhā gandhako jñeyo varṇaiḥ śvetādibhiḥ khalu /
{sulfur:: white}
śveto'tra khaṭikā prokto lepane lohamāraṇe //

Sulphur is indeed to be known as fourfold by colors, beginning with white:
The white here is called chalk-like, used in coating and the killing of metals;