chloropal

from The Century Dictionary.

• noun A hydrated silicate of iron, of a conchoidal fracture and earthy structure, and varying from yellow to green in color.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Min.) A massive mineral, greenish in color, and opal-like in appearance. It is essentially a hydrous silicate of iron.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun mineralogy A massive mineral, greenish in colour and opal-like in appearance, essentially a hydrous silicate of iron.