Syenite

Definitions

  • Webster's Revised Unabridged Dictionary
    • n Syenite (Min) Orig., a rock composed of quartz, hornblende, and feldspar, anciently quarried at Syene, in Upper Egypt, and now called granite.
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Century Dictionary and Cyclopedia
    • n syenite A rock composed of feldspar and hornblende, with or without quartz. The name syenites was given by Pliny to the red granitoid rock extensively quarried at Syene in Egypt. The term syenite was introduced into modem geological science by Werner, in 1788, bur. applied by him to a rock (from the Plauenscher Grund, near Dresden) not identical in composition with the syenites of Pliny, which latter is a hornblendic granite, or granite in which mica is replaced by hornblende, whereas the rock which Werner called syenite is mainly made up of a mixture of feldspar and hornblende; hence there has long been more or less confusion in regard to the nomenclature of this rock. The English and some continental geologists have defined syenite as an aggregate of quartz, feldspar, and hornblende; while the Germans have generally regarded the quartz as not being an essential constituent of the rock: this latter view is that which has been adopted in the most recent English geological and lithological works. Syenite is a rock thoronghly crystalline in texture, and in general it much resembles granite in its mode of occnrrence. The feldspathic ingredient is chiefly orthoclase, and this usually predominates considerably in quantity over the associated minerals; there is some triclinic feldspar present, however, in most syenites, and the same is true in regard to quartz, biotite, titanite, magnetite, apatite, zircon, and various other accessory minerals frequently found in small quantity in the granitic rocks. Sometimes the hornblende is replaced by augite; this variety is designated augite-syenite; that in which mica predominates is known as mica-syenite or minette. The range of syenite in geological age is similar to that of granite, and the frequent passage of one rock into the other shows how closely allied the two are, one result of which condition is that the nomenclature of the different varieties is correspondingly difficult. Typical syenite is by no means abundant, and in general the granitic rocks very considerably surpass the syenitic in economic importance. Also sienite.
    • n syenite In the quantitative system of classification (see rock), a proposed general field-term for a phaneric igneous rock composed of dominant feldspar of any kind, with subordinate amounts of mica, hornblende, pyroxene, or other minerals, and without a noticeable amount of quartz
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Chambers's Twentieth Century Dictionary
    • n Syenite sī′en-īt a rock composed of feldspar and hornblende
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Etymology

Webster's Revised Unabridged Dictionary
L. Syenites,sc. lapis,), from Syene, Gr.
Chambers's Twentieth Century Dictionary
From Gr. Syēnē, Syene in Egypt.

Usage

In literature:

Conspicuous among the trees, for its gigantic size, and bark coloured exactly like Egyptian syenite, is the burly Baobab.
"A Popular Account of Dr. Livingstone's Expedition to the Zambesi and Its Tributaries And of the Discovery of the Lakes Shirwa and Nyassa (1858-1864)" by David Livingstone
Traces of the force of the torrent are seen in the syenite and basalt boulders which encumber the course.
"How I Found Livingstone" by Henry M. Stanley
Granite Point exhibits trap dykes in syenite.
"Personal Memoirs Of A Residence Of Thirty Years With The Indian Tribes On The American Frontiers" by Henry Rowe Schoolcraft
The rock was syenite, so weathered as to resemble sandstone.
"Three Expeditions into the Interior of Eastern Australia, Vol 2 (of 2)" by Thomas Mitchell
The castle stands upon the summit of a small hill of syenitic rock.
"Rambles and Recollections of an Indian Official" by William Sleeman
The rocks are still syenite.
"The Last Journals of David Livingstone, in Central Africa, from 1865 to His Death, Volume I (of 2), 1866-1868" by David Livingstone
Some very fine syenite occurs in large blocks close to Moravicza, which might be very valuable if made more accessible.
"Round About the Carpathians" by Andrew F. Crosse
It was at this epoch that the rocks called feldspars, syenites, and porphyries appeared.
"A Journey to the Centre of the Earth" by Jules Verne
In the north, the principal rocks are granite and syenite.
"The International Monthly, Volume 3, No. 2, May, 1851" by Various
The material employed was limestone cased with syenite (granite from Syene), and the internal passages were lined with granite.
"Architecture" by Thomas Roger Smith
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