Plumbago

n.	1.	(Min.) Same as Graphite.
	2.	(Bot.) A genus of herbaceous plants with pretty salver-shaped corollas, usually blue or violet; leadwort.

Noun	1.	plumbago - used as a lubricant and as a moderator in nuclear reactors Synonyms: black lead, graphite
	2.	plumbago - any plumbaginaceous plant of the genus Plumbago

atomic number 6, black lead, C, carbon, graphite, lead, pencil, pencil lead