pleochroism

American  

[plee-ok-roh-iz-uhm] / pliˈɒk roʊˌɪz əm /

noun

1. the property of certain crystals of exhibiting different colors when viewed from different directions under transmitted light.

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pleochroism British  

/ ˌpliːəˈkrəʊɪk, plɪˈɒkrəʊˌɪzəm /

noun

1. a property of certain crystals of absorbing light to an extent that depends on the orientation of the electric vector of the light with respect to the optic axes of the crystal. The effect occurs in uniaxial crystals ( dichroism ) and esp in biaxial crystals ( trichroism )

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Other Word Forms

• pleochroic
  adjective

Etymology

Origin of pleochroism

First recorded in 1855–60; pleochro(ic) + -ism

Example Sentences

It is essentially a basic aluminium borosilicate, belonging to the orthorhombic system; it occurs usually in fibrous forms, of smalt-blue, greenish-blue, lavender or almost black colour, and exhibits strong pleochroism.

From Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 8 "Dubner" to "Dyeing" by Various

A very useful means of discriminating between certain stones is found in their dichroism, or, to use a more general term, pleochroism.

From Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 5 "Gassendi, Pierre" to "Geocentric" by Various

The pleochroism is strong, the pleochroic colours being usually green, yellow and brown.

From Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 6 "English Language" to "Epsom Salts" by Various

The last mentioned is a bright blue variety of hornblende with striking pleochroism.

From Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 10 "Echinoderma" to "Edward" by Various

Such an effect is called pleochroism, and crystals which show variations in their colour when viewed from different angles, or by transmitted light, are called pleochroic, or pleochromatic—from two Greek words signifying "to colour more."

From The Chemistry, Properties and Tests of Precious Stones by Mastin, John