to cocker is a form of:

Chrysolite



noun
1.
ថ្មមាស, ថ្មពណ៌មាស
ENGLISH MEANING
noun
1.
A mineral, composed of silica, magnesia, and iron, of a yellow to green color. It is common in certain volcanic rocks; -- called also olivine and peridot. Sometimes used as a gem. The name was also early used for yellow varieties of tourmaline and topaz.