tellurium is such a strange element to be representing Earth on the periodic table. think of the earthiest elements, and what comes to mind? carbon maybe, because it's in everything. silicon, because it's the workhorse of Earth's minerals. magnesium or calcium perhaps, because these are "earths" (alkaline earths) and found in many rocks. but tellurium?
tellurium doesn't even like being on Earth. Te is rare because it forms a gaseous hydride, H2Te, which leaked away slowly into space from the Earth's primordial atmosphere. in its elemental form, which does occasionally occur naturally, tellurium is semimetallic and brittle (I guess that's "earthier" in some vague sense than a malleable metal), but most of the Earth's tellurium is thinly distributed throughout various sulfide minerals, e.g. ores of copper or lead from which tellurium can be obtained as a byproduct of refining.
curiously, gold—which is most usually found in its elemental or "native" state, sometimes in "solid solution" with silver and other metals—forms mineral compounds only with tellurium; there's a sequence of gold and gold-silver telluride minerals like sylvanite and calaverite (hence we have the mining town of Telluride, CO, except..."These telluride minerals were never found near Telluride" via Wikipedia.)
maybe that's where the earthiness of tellurium is most visible. gold, the kingliest of metals, shining like the Sun, nevertheless bows to tellurium and consents to share some electron density.
~Chara
