More fragile than glass, tellurium is a very rare element found together with copper. Copper, too, happens to be rare in nature as well but - luckily - what little there is tends to bulk up together making recovery easy. In mining copper tellurium is recovered as a valuable impurity and due to its halfway-metal, halfway-something-else it has unique electrical properties that can be exploited. More uses have been employing tellurium and its growth in industry is really only checked by its rarity.

CAS 13494-80-9