tephr(o)-

Ash; ash-coloured.

Greek tephra, ash, ashes.

In geology, the form can refer to tephra, rock fragments and particles ejected by a volcanic eruption, as in tephrochronology, the dating of volcanic events by studying layers of tephra; tephroite is a manganese silicate, occurring in crystalline masses of an ashy grey or reddish colour; tephrite is a fine-grained basaltic rock.