Li3 is Lithium

Named after the Greek word for stone, lithos, lithium is the lightest known metal, never found alone (highly reactive), used in thermonuclear explosives, some anti-depressants, and lithium-ion batteries.  Now valued more than gold, its extra light weight is ideal for  electric cards.

The painting shows repeated L's, I's, and 3"s, in silver and olive green on brown paper.