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Taranakite
Current inventory:  1 gem
 

Taranakite

  
Taranakite is named after its disovery locality of the Sugar Loaf Islands, off Taranaki (now Port Taranaki), New Zealand.

Discovered in 1865;   IMA status:  Valid (pre-IMA; Grandfathered)

 

Chemistry

 

 

Chemical Formula:

K3Al5(PO4)2(PO3OH)6 •18H2O

 

Hydrated Potassium Aluminum Phosphate Hydroxide

Molecular Weight:

1342.30 gm

Composition:

Potassium

8.74 %

K

10.53 %

K2O

 

Aluminum

10.05 %

Al

18.99 %

Al2O3

 

Phosphorus

18.46 %

P

42.30 %

P2O5

 

Hydrogen

3.15 %

H

28.18 %

H2O

 

Oxygen

59.60 %

O

 

 

 

 

100.00 %

 

100.00 %

= TOTAL OXIDE

 

 

Classification

   

   

Mineral Classification:

Phosphates

Strunz 8th Ed. ID:

7/C.21-20

Nickel-Strunz 10th Ed. ID:

8.CH.25

 

8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H
2O
H : With large and medium-sized cations, RO
4:H2O < 1:1

Related to:

None

Varieties:

None

Synonyms:

Minervite, Palmerite

 

 

Crystal Data

   

   

Crystallography:

Trigonal - Hexagonal Scalenohedral

Crystal Habit:

Pseudohexagonal platy crystals, rarely to 0.5 mm; typically in compact nodular aggregates, pulverulent, powdery, flourlike to claylike, massive.

Twinning:

None

 

 

Physical Properties

   

 

Cleavage:

None

Fracture:

None

Tenacity:

Malleable, unctuous (having a greasy or soapy feel)

Moh's Hardness:

1.0 - 2.0

Density:

2.12 - 2.15 (g/cm3)

Luminescence:

None

Radioactivity:

Barely Detectable; GRapi = 128.51 (Gamma Ray American Petroleum Institute Units)

 

 

Optical Properties

   

   

Color:

Gray, yellowish white, white; colorless in transmitted light

Transparency:

Transparent, translucent, opaque

Luster:

n/a

Refractive Index:

1.500 - 1.510  Uniaxial ( - ) 

Birefringence:

0.006 - 0.007

Dispersion:

n/a

Pleochroism:

None

 

 

Occurances

   

   

Geological Setting:

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; the most common phosphate mineral in caves.

Common Associations:

Vashegyite, Leucophosphite, Minyulite, Francoanellite, Brushite, Ardealite, Strengite, Variscite, Vivianite

Common Impurities:

None

Type Locality:

Sugar Loaf Islands, off Taranaki (now Port Taranaki), New Zealand

Year Discovered:

1865

View mineral photos:

Taranakite Mineral Photos and Locations

 

 

More Information

   

   

 

Mindat.org
Webmineral.com

 

 


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. It is very soft, with a Moh's hardness of 1 - 2, lacks cleavage and is malleable and unctuous (having a greasy or soapy feel). Taranakite gems are extremely rare, very small and considered to be a gem 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) long.

Taranakite is also noted as being the first new mineral to be discovered in New Zealand. It was discovered in 1865 by Henry Robert Richmond (1829-1890), fourth superintendent of Taranaki, on the Sugar Loaf Islands of Taranaki, New Zealand. Taranakite was first analyzed and described by Scottish geologist Sir James Hector (1834-1907), and English analytical chemist William Skey (1835-1900). It was initially mistaken for Wavellite but was found to be a new mineral after analysis by Hector and Skey. James Hector was the first Director of New Zealand's Colonial Museum and Laboratory, with William Skey as its first analyst.

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" after Italian Professor Paride Palmeri, American Academy, Rome, Italy. These two minerals were later identified through X-ray powder diffraction as Taranakite and discredited in favor of Taranakite by historical priority.

Taranakite distribution: 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.
 

  
Taranakite
gems for sale:

Taranakite-001

Gem:

Taranakite

Stock #:

TARA-001

Weight:

0.0550 ct

Size:

4.04 x 3.45 x 1.65 mm

Shape:

Pear

Color:

Pale Yellowish Tan

Clarity:

Opaque

Origin:

Parwan Caves, Victoria, Australia

Treatment:

None (natural)

Price:

$220.00    [ Make an offer ]

Pictures are of the actual gem offered for sale.
Gem images are magnified to show detail.

Taranakite-001

This rare little gem comes from the Parawn lava caves, Bacchus Marsh, Victoria, Autralia.

 

 


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