schorl

American  

[shawrl] / ʃɔrl /

noun

1. Mineralogy. a black tourmaline.

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schorl British  

/ ʃɔːl /

noun

1. a black tourmaline consisting of a borosilicate of sodium, iron, and aluminium. Formula: NaFe 3 B 3 Al 3 (Al 3 Si 6 O 27 )(OH) 4

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Other Word Forms

• schorlaceous adjective

Etymology

Origin of schorl

First recorded in 1755–65, schorl is from the German word Schörl

Example Sentences

“Tourmaline hornfelses” are found sometimes near the margins of tourmaline granites; they are black with small needles of schorl which under the microscope are dark brown and richly pleochroic.

From Project Gutenberg

Greisen is closely connected with schorl rock both in its mineralogical composition and in its mode of origin.

From Project Gutenberg

In the tourmaline granites prisms of black schorl occur either singly or in stellate groups.

From Project Gutenberg

On its northern slope is a vast mass of schorl, the celebrated Roche Rock.

From Project Gutenberg

Structurally, therefore, these isles are a continuation of Land's End, but the granite has become less consistent and more friable; it is largely broken into felspar, quartz, and mica, with schorl, chlorite, and hornblende.

From Project Gutenberg