ide ▁is ▁the ▁in organ ic ▁comp ound ▁with ▁the ▁formula ▁C d S . ▁Cad m ium ▁sul f ide ▁is ▁a ▁yellow ▁solid . ▁It ▁occurs ▁in ▁nature ▁with ▁two ▁different ▁cry stal ▁structures ▁as ▁the ▁rare ▁min er als ▁green ock ite ▁and ▁ha w ley ite , ▁but ▁is ▁more ▁pre val ent ▁as ▁an ▁imp urity ▁subst itu ent ▁in ▁the ▁similarly ▁struct ured ▁z inc ▁or es ▁s phal er ite ▁and ▁wur tz ite , ▁which ▁are ▁the ▁major ▁economic ▁sources ▁of ▁cad m ium . ▁As ▁a ▁comp ound ▁that ▁is ▁easy ▁to ▁isol ate ▁and ▁pur ify , ▁it ▁is ▁the ▁principal ▁source ▁of ▁cad m ium ▁for ▁all ▁commercial ▁applications . ▁Its ▁v ivid ▁yellow ▁color ▁led ▁to ▁its ▁ad option ▁as ▁a ▁p ig ment ▁for ▁the ▁yellow ▁paint ▁" c ad m ium ▁yellow " ▁in ▁the ▁ 1 8 th ▁century . ▁ ▁Production ▁Cad m ium ▁sul f ide ▁can ▁be ▁prepared ▁by ▁the ▁precip itation ▁from ▁sol ub le ▁cad m ium ( II ) ▁sal ts ▁with ▁sul f ide ▁ion . ▁This ▁reaction ▁has ▁been ▁used ▁for ▁grav imet ric ▁analysis ▁and ▁qual itative ▁in organ ic ▁analysis . The ▁prepar ative ▁route ▁and ▁the ▁subsequent ▁treatment ▁of ▁the ▁product , ▁affect s ▁the ▁polym orph ic ▁form ▁that ▁is ▁produced ▁( i . e ., ▁cub ic ▁vs ▁hex ag onal ). ▁It ▁has ▁been ▁assert ed ▁that ▁chemical ▁precip itation ▁methods ▁result ▁in ▁the