Annabergite [Ni.sub.3](AS[O.sub.4])[sub.2][multiplied by]8[H.sub.2]O
Annabergite is a relatively rare mineral, occurring in open fractures mainly as clusters of transparent, pale green to bluish green and bright green prismatic crystals up to about 5 mm in length.
The Tynebottom mine has produced an interesting suite of nickel and cobalt-containing minerals including erythrite, safflorite, nickel-skullerudite, violarite, rammelsbergite, annabergite
, and some very attractive specimens of drusy calcite and "flowstone" colored pink to deep magenta by micro-inclusions of erythrite, or blue by copper salts.
In 1988 Lindsay Greenbank led a group from the British Geological Survey through the mine, and found a small cavity in the roof that yielded what is certainly the finest known annabergite
specimen from the Pennines (shown here).
On the old dumps of the Ightem mine, well-crystallized adamite occurs commonly in a gray-white dolomite--despite the carbonate milieu it is overwhelmingly arsenates (annabergite, conichalcite, adamite ...) which are present in this dolomite.
Associations include erythrite, annabergite, talmes-site, powellite, galena and native gold.
The best reported Bou Azzer annabergite specimens (Clavel and Elmaleh-Levy, 1978) are those found in an ore vein (designated as the Filon Nickeline--"Nickeline Vein") in the western part of the district, 6 km west-northwest of Bou Azzer.
In Vein 51, Ait Ahmane, annabergite formed by the hydrothermal alteration of gersdorffite has been found as beautiful green leafy crystals in quartz, with massive "garnierite" and pale green, microcrystalline, nickel-rich talmessite.
Specimens of chromite rich in secondary species, especially talmessite and annabergite, and also containing chromite grains, from Ait Ahmane.
Annabergite [Ni.sub.3](As[O.sub.4])[.sub.2] x 8[H.sub.2]O
The mineral also appears near grains of copper sulfide and as chrysocolla pseudomorphs; associated species include conichalcite, lavendulan, annabergite and erythrite.