Dalyite Mineral Data

General Dalyite Information

Chemical Formula:

K2ZrSi6O15

Composition:

Molecular Weight = 571.59 gm

Potassium 13.00 % K 15.66 % K₂O

Sodium 0.04 % Na 0.05 % Na₂O

Magnesium 0.09 % Mg 0.14 % MgO

Zirconium 14.36 % Zr 19.40 % ZrO₂

Titanium 0.75 % Ti 1.26 % TiO₂

Aluminum 0.05 % Al 0.09 % Al₂O₃

Iron 0.20 % Fe 0.28 % Fe₂O₃

Silicon 29.53 % Si 63.18 % SiO₂

Oxygen 41.99 % O

______ ______

100.00 % 100.06 % = TOTAL OXIDE

Empirical Formula:

K_1.9Fe³⁺_0.02Mg_0.02Na_0.01Zr_0.9Ti_0.09Al_0.01Si_6.01O₁₅

Environment:

A rare accessory in ejected blocks of alkalic granite in trachytic and basaltic tuffs (Ascension Island); in syenite (Serra de Agua de Pau, Azores); in lamproite (Cancarix, Spain).

IMA Status:

Valid Species (Pre-IMA) 1952

Locality:

Ascension Island. Link to MinDat.org Location Data.

Name Origin:

Named for Reginald Aldworth Daly (1871-1957), Professor of Geology, Harvard University, Cambridge, Massachusetts, USA.

Name Pronunciation:

Dalyite

Synonym:

ICSD 22323

PDF 23-1376

Dalyite Image

Images:

Dalyite Janhaugite

Comments: Tan crystalline dalyite (arrow) with reddish brown janhaugite.
Location: Gjerdingen, Nordmark, north of Oslo, Oslo, Norway. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Dalyite Crystallography

Axial Ratios:

a:b:c =0.9535:1:0.8941

Cell Dimensions:

a = 7.371, b = 7.73, c = 6.912, Z = 1; alpha = 106.1°, beta = 111.48°, gamma = 100° V = 346.75 Den(Calc)= 2.74

Crystal System:

Triclinic - Pinacoidal H-M Symbol ( 1) Space Group: P1

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

By Intensity(I/I_o): 3.08(1), 3.58(1), 4.2(1),

Physical Properties of Dalyite

Cleavage:

{101} Good, {010} Good, {100} Indistinct

Color:

Colorless.

Density:

2.84

Diaphaneity:

Transparent

Fracture:

Brittle - Generally displayed by glasses and most non-metallic minerals.

Hardness:

7.5 - Garnet

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Dalyite

Gladstone-Dale:

CI meas= 0.01 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.007 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.208,KPDmeas= 0.2073,KC= 0.2094
Ncalc = 1.59

Optical Data:

Biaxial (-), a=1.575, b=1.59, g=1.601, bire=0.0260, 2V(Calc)=80, 2V(Meas)=72.

Calculated Properties of Dalyite

Electron Density:

Bulk Density (Electron Density)=2.76 gm/cc
note: Specific Gravity of Dalyite =2.83 gm/cc.

Fermion Index:

Fermion Index = 0.03
Boson Index = 0.97

Photoelectric:

PE_Dalyite= 21.55 barns/electron
U=PE_Dalyite x r_electron= 59.57 barns/cc.

Radioactivity:

GRapi = 183.21 (Gamma Ray American Petroleum Institute Units)
Concentration of Dalyite per GRapi unit = 0.55 (%)

Estimated Radioactivity from Dalyite - barely detectable

Dalyite Classification

Dana Class:

72.02.01.01 (72)Phyllosilicate Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings

(72.02)with 4-, 6-, and 8-membered rings

(72.02.01)Dalylite group

72.02.01.01 Dalyite K2ZrSi6O15 P1 1

72.02.01.02 Davanite K2TiSi6O15 P1 1

72.02.01.03 Sazhinite-(Ce) Na2Ce[Si6O14(OH)]•n(H2O),(n>=1.5) Pmm2 mm2

72.02.01.04 Sazhinite-(La)! Na3La[Si6O15]•2(H2O) Pmm2 2/m 2/m 2/m

Strunz Class:

09.EA.25 09 - SILICATES (Germanates)

09.E - Phyllosilicates

09.EA -Single nets of tetrahedra with 4-, 5-, (6-), and 8-membered rings

09.EA.25 Dalyite K2ZrSi6O15 P1 1

09.EA.25 Davanite K2TiSi6O15 P1 1

Other Dalyite Information

References:

NAME( AntBidBlaNic2) PHYS. PROP.(AntBidBlaNic2) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Dalyite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info
15 - WWW-MINCRYST

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

Dalyite

K2ZrSi6O15
Dana No: 72.02.01.01 Strunz No: 09.EA.25
Locality:

Notes:

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