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 GEMSTONE SPECTRA

(EXCEL FILES)

   COLOURLESS STONES

   COLOURLESS STONES

  CS1  

 RED STONES  

  RD1 Dark red

   RD2 Pinkish red

  RD3 Orangy red

RD4 Slightly purplish red

  RD5  Purplish red

PINK STONES 

 PK1 Lilac pink

   PK2 Pink and orangy pink

PK3  Brownish and purplish pink

ORANGE STONES

OR1

YELLOW STONES

YL1

GREEN STONES

GN1 Green

GN2 Yellowish and greyish green

GN3 Bluish green

 GN4 Dark and brownish green

BROWN STONES

BN1 Light brown

BN2 Dark brown

BLUE STONES

BL1 Blue

BL2 Greenish blue

BL3 Lavender and indigo blue

VIOLET AND PURPLE STONES

VT - PL Violet and Purple

  Periodically other gemstones will be added to these files

 

 

Diffraction spectra of zircon (high type)

 

See my  DECLARATION OF COPYRIGHT

Colour Properties of Zircon (Hightype)

Colour

Many colours in various hues often with brownish overtones. Rarely blue or colourless. Heat treated stones Bright pale blue, dark purplish blue, orange or colourless.

Cause of  Colour

Uranium,  Thorium and rare earths may be present.

Optical Character

 Uniaxial positive.

Pleochroism

 Mostly noticeable to very weak but strong in deep blue and heat treated blue stones.

Colour change

Heat treated purplish blue stones appear bluish green in tungsten.

Spectrum; no polar, calibration in nm.

High type - 691; 683; 662/660; 653; 621; 615; 589; 562; 537; 516; 511;484; 460. Dominant 653 is diagnostic, stronger lines underlined, others weak. Heat treated pale blue and colourless stones -  653 and 660 possibly others but generally faint.

Ordinary ray

As no polar; but 662;653 are stronger. Lines at 621 and 615 are very weak or missing. .Heat treated stones  - any visible lines stronger.

Extraordinary ray

As no polar; but 683;662/660; are stronger. Lines at 621 and 615 are present.and stronger. Heat treated stones Little or no change.

Alpha ray

Not applicable

Beta ray

Not applicable

Gamma ray

Not applicable

Emission lines

No

Database reference

See all Excel files

Notes

Myanmar Mogok stones - Strong dark lines. Sri Lankan - Narrower lines but sharp.

 

Copyright John S. Harris 2000-2016

 

SPECTRA OF

 PRINCIPAL 

COMMERCIAL GEMS

ALEXANDRITE

ALMANDINE GARNET

CHRYSOBERYL

DIAMOND

     EMERALD     

GREEN JADEITE

PERIDOT

RUBY

BLUE SAPPHIRE  

RED SPINEL

GREEN & BLUE SPINEL

SYN. BLUE SPINEL  & Co. GLASS

SYN. COLOUR CHANGE CORUNDUM

ZIRCON (Low type)

Other pages are under construction.

COLOUR FILTERS

 (EXCEL FILES)    

CF1 Basic Colour Filters

CF2 Special Colour Filters

EDUCATIONAL C. D.

  A GUIDE TO THE   SPECTROSCOPE