Is malachite a rare-earth element?

Hassium is not a rare earth element; but is an artificial element, extremely rare and very difficult to obtain.

Tin is actually the 49nt most common element on earth, so yes i guess you CAN say it is rare, its mostly found in Boliva, Zaire, Malaysia , Idonesia :)

No. The rare earth elements are scandium, yttrium and the Lanthanides, which have atomic numbers ranging from 57 to 70 (lanthanum, neodymium, samarium, etc.). The atomic number for iron is 26.

No, argon is not part of the group known as rare earth elements. Rare earth elements are a series of 15 elements known as the lanthanides, (atomic numbers 57 through 71 - lanthanum through lutetium)...

Although very common throughout the universe, it is relatively rare on Earth because of its light weight.