Not beads this time but I just could not resist buying these onyx grapes when I saw them in a local market.
Onyx is a banded variety of the oxide mineral chalcedony. Agate and onyx are both varieties of layered chalcedony that differ only in the form of the bands: agate has curved bands and onyx has parallel bands. The colors of its bands range from white to almost every color (save some shades, such as purple or blue). Commonly, specimens of onyx contain bands of black and/or white.
This is one of a set of necklaces I was sent to restring and it contains extremely old Indian Agate beads.