Name Agate
Grey 
Origin Botswana. Grey with white/black/pink bands.
A fine-grained variegated chalcedony (a member of the quartz family, named in 1570), usually with colours arranged in stripes, blended in clouds or showing moss-like forms. Agates are generally formed by water seeping into cavities in volcanic rocks and depositing mineral salts in layers which over the centuries have hardened into varied-coloured bands of chalcedony. These bands are often concentric, producing beautiful patterns.