True granite according to modern petrologic convention contains both plagioclase and alkali feldspars.

The base structure becomes either < sup >-</ sup > or < sup > 2 -</ sup > There are 22 mineral species of feldspars, subdivided into two major subgroups — alkali and plagioclase — and two less common groups — celsian and banalsite.

Crystal twinning is common in feldspars, especially polysynthetic twins in plagioclase and Carlsbad twins in alkali feldspars.

Feldspar can be divided into two smaller subdivisions: alkali feldspars and plagioclase feldspars.

If the high temperature intermediate composition alkali feldspars are allowed to cool slowly, exsolution occurs and a perthite structure results.

They are exceedingly rich in alkalis and in alumina ( hence the abundance of felspathoids and alkali feldspars ) with silica varying from 50 to 56 %, while lime, magnesia and iron are never present in great quantity, though somewhat more variable than the other components.

Riebeckite-granites have close affinities to aplites, shown especially in the prevalence of alkali feldspars.

Dark rounded alkali feldspars, typically one centimeter or less in diameter, dominate this rock.

Perthite is used to describe an intergrowth of two feldspars: a host grain of potassium-rich alkali feldspar ( near K-feldspar, KAlSi < sub > 3 </ sub > O < sub > 8 </ sub >, in composition ) includes exsolved lamellae or irregular intergrowths of sodic alkali feldspar ( near albite, NaAlSi < sub > 3 </ sub > O < sub > 8 </ sub >, in composition ).

Closely related to the andrenas are the nomias or alkali bees.

The alkali metals are a group of chemical elements in the periodic table with very similar properties: they are all shiny, soft, silvery, highly reactive metals at standard temperature and pressure and readily lose their outermost electron to form cations with charge + 1.

The alkali metals are lithium ( Li ), sodium ( Na ), potassium ( K ), rubidium ( Rb ), caesium ( Cs ), and francium ( Fr ).

Experiments have been conducted to attempt the synthesis of ununennium ( Uue ), which is likely to be the next member of the group, but they have all met with failure .< ref name =" link "> However, ununennium may not be an alkali metal due to relativistic effects, which are predicted to have a large influence on the chemical properties of superheavy elements.

The gases are contained in a test-tube ( A ) standing over a large quantity of weak alkali ( B ), and the current is conveyed in wires insulated by U-shaped glass tubes ( CC ) passing through the liquid and round the mouth of the test-tube.

The terms " base " and " alkali " are often used interchangeably, particularly outside of a scientific context.

There are various definitions for alkali.

Alkali salts are soluble hydroxides of alkali metals and alkali earth metals, of which common examples are:

In this system, the alkali metals, alkaline earth metals, and transition metals, as well as the lanthanides and the actinides, are special groups of the metals viewed in a broader sense.

It is a soft, silvery-gold alkali metal with a melting point of 28 ° C ( 82 ° F ), which makes it one of only five elemental metals that are liquid at ( or near ) room temperature.

Many of the simple salts are hygroscopic, but less so than the corresponding salts of the lighter alkali metals.

Elements are trying to reach the low-energy noble gas configuration, and therefore alkali metals and halogens will donate and accept one electron, respectively, and the noble gases themselves are chemically inactive.

Geopolymer cements are made from mixtures of water-soluble alkali metal silicates and aluminosilicate mineral powders such as fly ash and metakaolin.

Salt-like carbides are composed of highly electropositive elements such as the alkali metals, alkaline earths, and group 3 metals including scandium, yttrium and lanthanum.

The graphite intercalation compound KC < sub > 8 </ sub >, prepared from vapour of potassium and graphite, and the alkali metal derivatives of C < sub > 60 </ sub > are not usually classified as carbides.

Care must be taken that the raw materials have not reacted with moisture or other chemicals in the environment ( such as alkali or alkaline earth metal oxides and hydroxides, or boron oxide ), or that the impurities are quantified ( loss on ignition ).

The alkali metal ions are small and mobile ; their presence in glass allows a degree of electrical conductivity, especially in molten state or at high temperature.

The raw materials are prepared by different curing, acid, and alkali processes which are employed to extract the dried collagen hydrolysate.

All industrial processes are based on neutral or acid pH values because though alkali treatments speed up conversion, they also promote degradation processes.

It is also the most resistant against weathering ( alkali ions leaching out of the glass, while staining it ).

The most common commercial glasses contain both alkali and alkaline earth ions ( usually sodium and calcium ), for easier processing and satisfying corrosion resistance.

It is the second most electropositive of the non-radioactive alkali metals and melts at a temperature of.

In the oxidation state + 1 most compounds closely resemble the corresponding potassium or silver compounds ( the ionic radius of thallium ( I ) is 1. 47 Å while that of potassium is 1. 33 Å and that of silver is 1. 26 Å ), which was the reason why thallium was sometimes considered to be an alkali metal in Europe ( but not in England ) in the years immediately following its discovery.

Relative to most common igneous rocks, basalt compositions are rich in MgO and CaO and low in SiO < sub > 2 </ sub > and the alkali oxides, i. e., Na < sub > 2 </ sub > O + K < sub > 2 </ sub > O, consistent with the TAS classification.

It is slightly soluble in water ; soluble in dilute acids, trichloroethylene, dimethylformamide, most organic solvents, insoluble with aqueous alkali.

The types of glass fiber most commonly used are mainly E-glass ( alumino-borosilicate glass with less than 1 % w / w alkali oxides, mainly used for glass-reinforced plastics ), but also A-glass ( alkali-lime glass with little or no boron oxide ), E-CR-glass ( alumino-lime silicate with less than 1 % w / w alkali oxides, has high acid resistance ), C-glass ( alkali-lime glass with high boron oxide content, used for example for glass staple fibers ), D-glass ( borosilicate glass with high dielectric constant ), R-glass ( alumino silicate glass without MgO and CaO with high mechanical requirements ), and S-glass ( alumino silicate glass without CaO but with high MgO content with high tensile strength ).

In a sequential leaching experiment on ash from the 1980 eruption of Mount St. Helens, chloride salts were found to be the most readily soluble, followed by sulphate salts Fluoride compounds are in general only sparingly soluble ( e. g. CaF < sub > 2 </ sub >, MgF < sub > 2 </ sub >), with the exception of fluoride salts of alkali metals and compounds such as calcium hexafluorosilicate ( CaSiF < sub > 6 </ sub >).

The elements in period 2 often have the most extreme properties in their respective groups ; for example, fluorine is the most reactive halogen, neon is the most inert noble gas, and lithium is the least reactive alkali metal.

Other alkali metals can be used in place of sodium, and most alcohols can be used in place of methanol.

Some donors have fewer valence electrons than the host, such as alkali metals, which are donors in most solids.

Nonactin is known for its ability to form complexes with alkali cations, most notably potassium and sodium.

The most common mineral assemblage of granulite facies consists of antiperthitic plagioclase, alkali feldspar containing up to 50 % albite and Al < sub > 2 </ sub > O < sub > 3 </ sub ></ tt >- rich pyroxenes.

Scientists at Indian Agricultural Research Institute, Delhi, genetically modified basmati to produce a hybrid semi-dwarf plant which had most of the good features of traditional basmati ( grain elongation, fragrance, alkali content ).

In most countries high-level radioactive waste has been incorporated into alkali borosilicate or phosphate vitreous waste forms for many years and vitrification is an established technology.

This form of direct optical excitation is generally limited to experiments with the alkali metals because the ground state binding energy in other species is generally too high to be accessible with most laser systems.

The most common electrowon metals are lead, copper, gold, silver, zinc, aluminium, chromium, cobalt, manganese, and the rare-earth and alkali metals.

The most mineralogically interesting are the associated agpaitic ( alkali rich, low aluminium and silicon ) pegmatites, the intrusive breccias, and the hornfels derived from the metasomatized sedimentary wall rocks.

As originally conceived, species within the Hymenochaetales had several morphological features in common, notably brown or brownish basidiocarps ( fruit bodies ) that turn black in alkali, hyphae lacking clamp connections, and the presence ( in most species ) of characteristic setae ( thick-walled, thorn-shaped cystidia, visible under a hand lens ).