🖋️⚪️⚫️

#coal #black substance #writing black #kcalb nobrac #black mark #dark material

🦑✒️⚫

#squid #writing ink comparison #black substance #cephalopod #marine biology

⚫⚲️

#black oil #thick liquid #black substance #tar #crude oil #viscosity

⚫💧💲

#black liquid #valuable resource #oil price #energy cost #petroleum value #black substance #liquid gold