Taranakite is a hydrated aluminium
phosphate mineral which is a secondary mineral formed from
phosphatic solutions derived from bird or bat guano
reacting with clays or aluminous rocks under perenially
damp conditions in caves and along sea coasts. Taranakite forms as
very small white, pale yellow, or gray crystals, which are typically found in
nodular aggregates or crusts. Gems are very, very rare
(if available at all), very small, not particularily
attractive and are mostly just a collector's curiosity
gem. Taranakite gems are extremely rare and very small
and could be considered a collector's oddity.
Taranakite crystallizes in the hexagonal system
and until 2009, was noted as having the longest crystallographic axis of any known mineral; the c-axis of the Taranakite unit cell is
95.05 Angstroms (9.505 nanometers) long. In 2009
however, Byzantievite was approved as a new mineral
having a c-axis of 102.145 Angstroms (10.214 nanometers)
is also noted as being the first new mineral to be discovered
in New Zealand. Taranakite was first described in 1865 by James Hector,
a geologist, and William Skey, a colonial New Zealand Government analyst. The material had been found by H. Richmond on the Sugar Loaf Islands of Taranaki, New Zealand.
Taranakite was initially mistaken for Wavellite but
was found to be a new mineral after analysis by Skey.
Taranakite was later
rediscovered in two cave locations and given two new
names. In 1894, Armand Gautier described a mineral which he called "Minervite" from caves at
Grotte de Minerve in Hérault, France
and argued that it formed from decomposing guano and animal remains
reacting with clays. In 1904 Eugenio Casoria found a mineral under a guano layer at
Monte Alburno, Italy which he called "Palmerite". These two minerals were later identified through
X-ray powder diffraction as Taranakite and discredited in favor of Taranakite by historical priority.
From the Sugar Loaf Islands, near New Plymouth, Taranaki
Peninsula, New Zealand. On Réunion Island, Indian Ocean;
Island Leones, Patagonia, Argentina; King George Island,
Maritime Antarctic. In Australia, in the Russenden Cave,
Queensland; the Skipton lava tube caves, 40 km southwest
of Ballarat, Victoria; in caves at Mimegarra, Western
Australia; and the Jenolan Caves, New South Wales. In
the Yangsue Posayen Cave, 20 km south of Guilin, Guangxi
Province, China. From the Niah Great Cave, Sarawak,
Malaysia. In the Onino-Iwaya Cave, Hiroshima Prefecture,
Japan. From the Tour Combes Cave, near Oran, Algeria.
In Etienne’s Cave, and well-crystallized in Christmas
Cave, Transvaal, South Africa. From the Bacho Kuo Cave,
Bulgaria. In the Minerva Grotto, Fauzan, Hérault, France.
In Italy, in the Castellana Cave, south of Bari, Puglia;
on Monte Alburno, near Controne, Salerno. In the USA,
in the Pig Hole Cave, Giles County, Virginia; and the
Low Water Bridge Cave, Greene County, Missouri. Additional
localities are known.