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INVESTIGATIONS

Stone

RI min

RI max

Biref min

Biref max

Dens min

Dens max

Colour

Location

Info

ne min

ne max

no min

no max

Spectrum

UVS

UVL

Reference

Friedelite

1.63

1.657

0.027

0.027

3.063

3.069

rose red, carmine red

Kalahari Manganese Field, Kuruman, South Africa

only cryptocrystalline, chelsea: vivid red

1.630

1.630

1.657

1.657

band ferom 535 to 595nm, general absorption from 400 to 480nm

inert

inert

Gems & Gemology 1982 Winter p221-224

Friedelite

1.65

 

 

 

3.04

3.19

orange red

 

approximate RI, aggregate, translucide

 

 

 

 

 

 

 

Zeitschrift der Deutschen Gemmologischen Gesellschaft 2018 67/1-2 p5-7

 

TABLES         (friedelite=monoclinic ! pseudo-uniaxial)

Stone

RI min

RI max

Biref min

Biref max

Dens min

Dens max

ne min

ne max

no min

no max

Reference

Friedelite

1.618

1.658

0.028

0.036

3

3.1

 

 

 

 

Gemmo.eu 2019

Friedelite

1.62

1.664

0.029

0.035

3.04

3.19

1.620

1.629

1.654

1.664

Tables of Gemstone Identification, Roger Dedeyne, Ivo Quintens, 2007 

Friedelite

1.625

1.664

0.03

0.03

3.04

3.07

1.625

1.629

1.654

1.664

Joel Arem, Color Encyclopedia of Gemstones, 1987 

Friedelite

1.625

1.664

0.029

0.035

3.06

3.19

 

 

 

 

Bestimmungstabellen für Edelsteine, Birgit Günther, 1981 

Friedelite

1.625

1.664

0.029

0.035

3.04

3.19

1.625

1.630

1.654

1.664

Gemme, Dati per l'identificazione, P. De Stefano et al, 1993 

Friedelite

1.625

1.664

0.03

0.03

3.04

3.07

 

 

 

 

http://www.gemmology.be 

Friedelite

1.625

1.664

0.03

0.03

3.04

3.07

1.625

1.629

1.654

1.664

http://www.geminterest.com 

Friedelite

1.627

1.663

0.032

0.035

3.04

3.19

1.627

1.630

1.659

1.663

Gemmological Tables, Ulrich Henn, 2004 

Friedelite

1.629

1.664

0.035

0.035

3.06

3.19

 

 

 

 

Gems, R Webster, 5th edition 1994 

Friedelite

1.63

1.66

0.03

0.03

3.05

3.09

 

 

 

 

Tabellen zur Edelstein-Bestimmung, Pschichholz FGA, 1975 

Friedelite

1.64

1.65

 

 

3.07

3.07

 

 

 

 

John Sinkakas, Gemstone and mineral data book,1972 

 

CAUSE OF COLOUR

Stone

Colour

Cause of colour

Reference

Friedelite

red

Mn?

Gems & Gemology 1982 Winter p224

Friedelite

red

Mn²+

https://www.dgemg.com/images/NewsletterJanuar2018/Friedelit-Newsletter-Januar-2018.pdf

 

MINERAL INCLUSIONS

 

LOCALITIES

STONE

LOCALITIES

REFERENCE

Friedeliet

Kalahari Manganese field

Kuruman, Kalahari

Cape Province

Zuid-Afrika

Gems & Gemology 1982 Winter p 224







 

CHEMICAL DATA

Stone

Colour

Locality

Reference

SiO2

Al2O3

MnO

MgO

FeO

Na2O

Cl

Friedelite

 

Kalahari Manganese Field, Kuruman

South Africa

Gems & Gemology 1982 Winter p 224

35.82

0.06

52.33

1.43

1.29

0.04

3.59