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vitrite

A coal microlithotype group that contains vitrinite macerals totalling at
least 95%. CF:liptite; vitrain. AGI

vitro-

Prefix meaning glassy.

vitroclarain

A rock-type coal consisting of vitrinite (collinite or telinite) and other
macerals, mainly exinite, and in which the other macerals exceed vitrinite
in quantity. CF:clarovitrain

vitroclastic

Pertaining to a pyroclastic rock structure characterized by fragmented
bits of glass; also, said of a rock having such a structure. AGI

vitrodurain

Durain in which much vitrain is present. Judged obsolete by the Heerlen
Congress of 1935. CF:durovitrain

vitrofusain

A coal constituent transitional between vitrain and fusain, and showing
plant cell structure. The cell walls are soaked with vitrain, where the
cell cavities are empty. It is not a mixture but a transition. Accepted by
the Heerlen Congress of 1935 to designate material transitional between
vitrain and fusain with fusain being predominant. CF:fusovitrain
AGI

vitrophyre

Any porphyritic igneous rock having a glassy groundmass. Adj: vitrophyric.
CF:felsophyre; granophyre. Syn:glass porphyry

vitrophyric

Said of a porphyritic igneous rock having large phenocrysts in a glassy
groundmass. AGI

vivianite

a. A monoclinic mineral, 2[Fe3 (PO4 )2 .8H2 O];
colorless where fresh; turning blue on oxidation; soft; a secondary
mineral found in ore deposits and pegmatites, in clays associated with
bone and other organic remains, and in anaerobic lake sediments.
Syn:blue iron earth; blue ocher; Prussian blue.
b. The mineral group annabergite, baricite, hoernesite, koettigite,
parasymplesite, and vivianite.

vlasovite

A monoclinic and triclinic mineral, Na2 ZrSi4 O11 ;
forms colorless crystals in the contact zone of the Lovozero massif, Kola
Peninsula, Russia. It is related to narsarsukite.

V-method of roasting

The introduction of a supplementary roast heap between each two regular
heaps, so that, if left untouched, there would be a continuous and
unbroken roast heap the entire length of the roast yard. Fay

vogesite

A lamprophyre composed of hornblende phenocrysts in a groundmass of alkali
feldspar and hornblende. Clinopyroxene, olivine, and plagioclase feldspar
also may be present. Vogesite contains less biotite than minette. The
name, given by Rosenbusch in 1887, is for the Vosges Mountains, France.
AGI

vogle

See:vug

voglianite

a. A soft, green, basic uranium sulfate, found in nodules or as earthy
coatings. Standard, 2
b. Validity of species is doubtful. All existing specimens, upon
examination, have proved to be cuprosklodowskite. Crosby; Dana, 2
c. A variety of zippeite(?).

voglite

A monoclinic mineral, Ca2 Cu(UO2 )(CO3 )4 .6H
2 O(?) ; strongly radioactive; emerald to grass green; an alteration
product of uraninite associated with liebigite.

void

a. A general term for pore space or other openings in rock. In addition to
pore space, the term includes vesicles, solution cavities, or any primary
or secondary openings. Syn:pore; interstice. AGI
b. That portion of a borehole from which the core could not be recovered.
Long

void ratio

The ratio of the volume of void space to the volume of solid substance in
any material consisting of voids and solid material, such as a soil
sample, sediment, or sedimentary rock. Symbol e. Syn:voids ratio
AGI

voids ratio

See:void ratio

vol

See:vole

volatile

Readily vaporizable. AGI

volatile combustibles

See:volatile matter