carbona

from The Century Dictionary.

• noun In mining, a mass of stanniferous rock, irregular in form, and not possessing the general character of a lode. Such a mass, however, is ordinarily subordinate to a lode in its immediate vicinity. The carbona is in some respects analogous to the “pipes” and “flats” of the North of England lead-mines. The carbona of the St. Ives lode in Cornwall, England, was one of the most remarkable of these occurrences, and one of the first to which this name was given. It was composed of feldspar, quartz, black tourmalin (schorl), tin ore (cassiterite), and some cupriferous ore. It also contained fluor-spar, which was not present in the lode itself.