Actually, there are no known rocks that begin with y. However, there are minerals such as Yellow Copperas, Yellow Ochre, Yttro Cerite, and Yttro Columbite. For more details on these minerals, check out probertencyclopaedia.com. I myself have been looking for a rock that starts with Y. Sorry, I haven't found any. But, again with the minerals, I hope it helps!

'it is a happy cerite'

'cierta' (as against 'cerita') = certain, sure

Terbium is a chemical element, atomic number 65, chemical symbol Tb. It is silvery-white in colour, malleable, ductile, and present in many minerals, including cerite, gadolinite, and monazite.

Gadolinium is named from the mineral gadolinite, in turn named forFinnish chemist and geologist Johan Gadolin.[3] In 1880, the Swisschemist Jean Charles Galissard de Marignac observed the spectroscopic lines from gadolinium in samples of gadolinite (which actually contains relatively little gadolinium, but enough to show a spectrum) and in the separate mineral cerite. The latter mineral proved to contain far more of the element with the new spectral line. De Marignac eventually separated a mineral oxide from cerite, which he realized was the oxide of this new element. He named the oxide "gadolinia". Because he realized that "gadolinia" was the oxide of a new element, he is credited with discovery of gadolinium. The French chemistPaul Émile Lecoq de Boisbaudran carried out the separation of gadolinium metal from gadolinia in 1886.

According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 6 words with the pattern CERI--. That is, six letter words with 1st letter C and 2nd letter E and 3rd letter R and 4th letter I. In alphabetical order, they are:

cerias

cering

ceriph

cerise

cerite

cerium