from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A mineral, magnesium-iron silicate hydroxide, (Mg,Fe)7Si8O22(OH)2.
from The Century Dictionary and Cyclopedia
- n. A variety of rhodonite or manganese silicate, occurring at Cummington, Massachusetts.
- n. An iron-magnesia variety of amphibole from the same locality.
Cummington + -ite, since it was originally discovered in Cummington, Massachusetts. (Wiktionary)