Chemical Formula: SiO2

Chemical Name: Silicon Dioxide

Mineral Class: Tectosilicate

Mineral Notes: Agate is a term applied not to a distinct mineral species, but to an aggregate of various forms of silica, chiefly Chalcedony. Most Agates occur as nodules in volcanic rocks or ancient lavas where they represent cavities originally produced by gasses in the molten mass which were then filled, wholly or partially, by siliceous matter deposited in regular layers upon the walls. Stalactitic Agate forms when the agate forms in elongated masses within the cavity usually by slow dropwise deposition of material.

Description: A large fragment of a volcanic nodule. The specimen consists of the nodule wall lined by a very attractive deposit of orange coloured Stalactitic Agate. Individual columnar formations are easily seen. Whilst the mass of the agate is in its Chalcedony form, the outside is lined by small quartz crystals. A very aesthetic display specimen.

Location: Ait Aourir, Morocco.