Londonite Mineral Data

Londonite Mineral Data

[On-Line Catalogue] [On-Line Auctions] [eBay] [Contact Us] [Policies]
We specialize in fine European and Asian Mineral Specimens
Heliodor is based in Prague, Czech Republic

General Londonite Information

Chemical Formula:

CsAl4Be4(B,Be)12O28

Composition:

Molecular Weight = 810.52 gm

Cesium 8.20 % Cs 8.69 % Cs₂O

Potassium 1.93 % K 2.32 % K₂O

Rubidium 1.05 % Rb 1.15 % Rb₂O

Beryllium 5.56 % Be 15.43 % BeO

Aluminum 13.32 % Al 25.16 % Al₂O₃

Boron 14.67 % B 47.24 % B₂O₃

Oxygen 55.27 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Cs_0.5K_0.4Rb_0.1Al₄Be₄B₁₁BeO₂₈

Environment:

Found in miarolitic cavities. Cs-analogue of rhodizite.

IMA Status:

Approved IMA 1999 (Dana # Added)

Locality:

Central units or the Antandrokomby, Antsonombato, and Ampanivana granitic pegmatites in Central Madagascar. Link to MinDat.org Location Data.

Name Origin:

Named for David London (1953-), petrologist at the University of Oklahoma, Oklahoma, USA.

Synonym:

IMA1999-014

Londonite Image

Images:

Londonite

Comments: A dodecahedral crystal of londonite.
Location: Antandrokomby pegmatite, Manandona valley, Sahatany Valley, Betafo - Antsirab? region, Antananarivo Province, Madagascar. Scale: Crystal size 7 mm.
© Thomas Witzke / Abraxas-Verlag

Images:

Londonite

Comments: A yellow , lustrous, well developed londonite crystal 1.2 cm. on matrix.
Location: Antandrokomby, Sahatany valley, Madagascar. Scale: Crystal size 1.2 cm.
© Sandro Maggia/Minernet.it

Londonite Crystallography

Cell Dimensions:

a = 7.3205, Z = 1; V = 392.30 Den(Calc)= 3.43

Crystal System:

Isometric - HextetrahedralH-M Symbol (4 3m) Space Group: P 43m

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 2.9898(1)(211), 2.1132(0.7)(222), 2.441(0.5)(300,221),1.7759(0.4)(410,322), 1.9568(0.35)(321), 3.276(0.35)(210), 2.208(0.3),

Crystal Structure:

Mouse
drag1 - LMB Manipulate Structure
drag2 - RMB Resize/Rotate
Keyboard
S - Stereo Pair on/off
H - Help Screen
I - Data Info
A - Atoms On/Off
P - Polyhedra On/Off
B - Bonds On/Off
Help on Above

Taxer K J , Buerger M J , Zeitschrift fur Kristallographie , 125 (1967) p.423-436, The crystal struture of rhodizite, Note: name of mineral altered according to IMA decision in 1999, to name the Cs dominant phase: londonite, Locality: Manjaka, Madagascar

Physical Properties of Londonite

Cleavage:

None

Color:

Colorless, White, Yellow.

Density:

3.34

Diaphaniety:

Transparent

Fracture:

Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments.

Habit:

Euhedral Crystals - Occurs as well-formed crystals showing good external form.

Hardness:

8 - Topaz

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Londonite

Gladstone-Dale:

CI meas= -0.002 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.024 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.202,KPDmeas= 0.2075,KC= 0.2071

Optical Data:

Isotropic, n=1.693.

Calculated Properties of Londonite

Electron Density:

r_electron=3.21 gm/cc
note: r_Londonite=3.34 gm/cc.

Fermion Index

Fermion Index = 0.08505
Boson Index = 0.91495

Photoelectric:

PE_Londonite= 34.34 barns/electron
U=PE_Londonite x r_electron= 110.34 barns/cc.

Radioactivity:

GRapi = 457.11 (Gamma Ray American Petroleum Institute Units)

Estimated Radioactivity from Londonite - barely detectable

Londonite Classification

Dana Class:

25.8.2.2 (25)Anhydrous Borates Containing Hydroxyl or Halogen

(25.8)Dana Type

(25.8.2)Dana Group

25.8.2.1 Rhodizite (K,Cs)Al4Be4(B,Be)12O28 P 43m 4 3m

25.8.2.2 Londonite ! CsAl4Be4(B,Be)12O28 P 43m 4 3m

Strunz Class:

V/L.02-30 V - Nitrates, Carbonates and Borates

V/L - Shelly borates with [BO2]1- to [B6O10]2-

V/L.02 - Hambergite - Rhodizite series

V/L.02-10 Hambergite Be2BO3(OH) P bca 2/m 2/m 2/m

V/L.02-20 Rhodizite (K,Cs)Al4Be4(B,Be)12O28 P 43m 4 3m

V/L.02-30 Londonite CsAl4Be4(B,Be)12O28 P 43m 4 3m

Other Londonite Information

References:

NAME( AmMin, Vol 87, p 356) PHYS. PROP.(AmMin, Vol 87, p 356) OPTIC PROP.(AmMin, Vol 87, p 356)

See Also:

Links to other databases for Londonite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - Google Images
4 - Google Scholar
5 - Handbook of Mineralogy (MinSocAm)
6 - Handbook of Mineralogy (UofA)
7 - MinDAT
8 - MinMax(Deutsch)
9 - MinMax(English)
10 - Mineralienatlas (Deutsch)
11 - QUT Mineral Atlas
12 - Ruff.Info

Search for Londonite using:

[ALTAVISTA] [AOL] [All-The-Web] [HotBot] [Ixquick] [MAMMA] [MSN.COM] [Netscape] [Scirus] [Teoma] [Wikipedia] [YAHOO]

Visit our Advertisers for Londonite :

AA Mineral Specimens

B & L Fine Minerals

Dan Weinrich Fine Minerals

Dan Weinrich Auctions

John Betts Fine Minerals

Mason's Minerals

Mineral News

Mineral of the Month Club

MineralsWeb Fine Minerals

The GeoZone

Wrights Rock Shop

Translate Londonite Mineral Data :

Ask about Londonite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

Print or Cut-and-Paste your Londonite Specimen Label here :

Londonite

CsAl4Be4(B,Be)12O28
Dana No: 25.8.2.2 Strunz No: V/L.02-30
Locality:

Notes: