It is referred to genus 16 of the olivine basalts, and is remarkable for the flow arrangement not only of the felspar-lathes but also of the smaller olivine crystals.
It contains abundant olivine but no other phenocrysts and very scanty interstitial glass, whilst the felspar-lathes average ·1 mm.
Many of the rocks are grey basalts with the olivinemore or less hematised; but the majority are blackish with the olivine usually more or less serpentinised.
These rocks are basaltic andesites and are neither vesicular nor scoriaceous, and come near the basalts of the Kiombo flow which, however, contain some olivine (see page 92).
The rocks composing these dykes are somewhat doleritic basaltic andesites, olivine being very rare or absent.
The olivine phenocrysts, of which the larger are 3 to 4 mm.
They contain microporphyritic olivine in abundance, which is usually more or less hæmatised and in extreme cases of the change looks like brown mica.
Here there is a great abundance of microporphyritic olivine in a groundmass of parallel felspar-lathes and augite grains; but the felspars are unusually small, averaging ·1 mm.
Then a smile lit up his olivine features, and he spoke a few words to one of his men.
True olivine (the peridot or the chrysolite of the trade) is of a fine leaf-green or bottle-green shade in the peridot.
The luster of olivine (whether of the peridot shade or not) is oily, and this may serve to distinguish it from tourmaline (which it may resemble in color).
True olivine (the peridot and the chrysolite of the trade).
Peridot, and the brighter olivine or chrysolite, while of the same mineral species, do not seem to occur together.
So also Bronzite (Enstatite) and Olivine have been met with in meteorites shown by analysis to come remarkably near to these minerals in ordinary rocks.
Presently the Indian messenger returned with a faint trace of a smile on his olivine features.
As was noted by Hague and Iddings, the hypersthene and olivine play a like role, the former occurring when the silica percentage is somewhat higher than in basalt.
Of the darker phenocrysts, the pyroxenes are more abundant than the olivine or hornblende.
This petrographical study showed that "Mount Rainier is formed almost wholly of hypersthene andesite, with different conditions of groundmass and accompanied by hornblende and olivine in places.
It also surrounds olivine in this same rock,[29] which is a hypersthene-andesite, the hornblende and olivine being only accessory.
Olivine occurs in certain of the Rainier lavas, in stout prisms somewhat rounded and often with reddened borders.
In the more basic phases anhedrons of augite and of olivine appear, and magnetite grains are usually present.
Hypersthene is not the prevailing pyroxene, and olivine is usually present, often in such abundance as to make the rock a basalt.
The olivine varies much in relative abundance, so as to be considered now an accessory and now an essential constituent, and in the latter case the rock is a basalt.
The hypersthene-augite olivine variation, already referred to, doubtless well expresses the chemical composition of the magma, and deserves to be taken as the chief criterion in the classification of the lavas.
I could discover no scoriae amongst the ejected materials, but balls of olivine and other volcanic substances are mentioned as having been found.
Olivine rarely occurs as an ingredient of the groundmass.
In microscopic section the olivine is pale green or colourless, and is very frequently more or less altered to serpentine.
Olivine and augite are the commonest porphyritic minerals in basalts, the former green or yellowish (and weathering to green or brown serpentine), the latter pitch-black.
Chassigny, consisting ofolivine with enclosed chromite, and thus mineralogically similar to a terrestrial dunite.
Angra dos Reis, consisting almost wholly of augite; olivine is present in small proportion.
It is supposed to have formed by the alteration ofolivine and pyroxene in the igneous rocks.
This lava is of a pale grey colour, fusing into a black enamel; its fracture is rather earthy and concretionary; it contains olivine in small grains.
The mass contains numerous broken crystals of olivine and augite, and small particles of black and brown scoriae; it is often traversed by thin seams of calcareous matter.
Small streams of black, basaltic lava, containing olivine and much glassy feldspar, have flowed from many, but not from all of these craters.
Should we conclude from this position that they are of more recent formation than the lithoid basaltic lava, which contains olivine and augite?
Their black augite and yellow green olivine are also easily detected in hand specimens.
The former consist mainly of plagioclase, leucite and augite, while the latter contain olivine in addition.
The commonest ferromagnesian mineral is augite (sometimes rich in soda), with olivine in the more basic varieties.
The leucite-basalts belong to more basic types and are rich in olivine and augite.
In olivine the black enclosures are not thin laminae, but branching growths resembling pieces of moss.
The olivine is colourless in itself, but in most cases is altered to green or yellow serpentine, often with bands of dark magnetite granules along its cleavages and cracks.
When these rocks become fine-grained they pass gradually into ophitic diabase and dolerite; only very rarely does olivine enclose felspar in this way.
Te Paheka's olivine features were wreathed in smiles when Malcolm entered his ward.
His well-developed muscles rippled under his olivine skin.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "olivine" in a variety of sentences. We hope that you will now be able to make sentences using this word.
