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Kentbrooksite
Current inventory:  0 gems
 

Chemistry:  (Na,REE)₁₅(Ca,REE)₆(Mn2+Zr₃Nb[Si₂₅O₇₄]F₂ · 2(H₂O)

Discovered in 1996;   IMA status: Valid (IMA Approved).
Kentbrooksite is named after Dr. C. Kent Brooks (1943-), leader of fourteen geological expeditions to the Kangerdlugssuaq area of east Greenland.

Classification

Mineral Classification:

Silicates

Strunz 8th Ed. ID:

8/E.23-20

Nickel-Strunz 10th Ed. ID:

9.CO.10

9 : SILICATES (Germanates)
C : Cyclosilicates
O : [Si₉O₂₇]₁₈- 9-membered rings

Related to:

Eudialyte group; Eudialyte - Alluaivite Series

Crystal Data

Crystallography:

Trigonal - Ditrigonal Pyramidal

Crystal Habit:

Anhedral to subhedral aggregates to 2cm

Twinning:

None

Physical Properties

Cleavage:

None

Fracture:

Uneven

Tenacity:

Brittle

Hardness (Mohs):

5.0 - 6.0

Density:

3.07 - 3.10 (g/cm³)

Luminescence:

None

Radioactivity:

Weak; GRapi = 29,710.44

Optical Properties

Color:

Yellowish Brown

Transparency:

Transparent, Translucent

Luster:

Vitreous

Refractive Index:

1.623 - 1.628  Uniaxial ( - )

Birefringence:

0.005

Dispersion:

Weak

Pleochroism:

None

Occurances

Geological Setting:

n/a

Common Associations:

n/a

Type Locality:

Amdrup Firth, Kangerlussuaq complex, Kangerlussuaq Firth, Tunu (East Greenland) Province, Greenland

Year Discovered:

1996

View mineral photos:

Kentbrooksite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Kentbrooksite is an extremely rare mineral that is a manganese and fluorine rich member of the Eudialyte group of minerals. It is primarily found at Mt Saint-Hilaire, Quebec, Canada; Kangerlugssuaq Firth, Greenland; Telemark, Norway; Kola Peninsula, Russia; and Tien Shan Mts, Tajikstan. Gem quality crystals are extremely rare and small. Kentbrooksite contains several Rare Earth Elements (REE) such as Lanthanum (La), Cerium (Ce), Praeseodymium (Pr), Neodymium (Nd) and Samarium (Sm) and therefore is weakly radioactive as defined in 49 CFR 173.403 (greater than 70 Bq/gram).
 

  
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