620 



QUARTERN 



QUARTZ 



Quartern i* a term employed in Mime part* of 

 Great Britain to designate tlie fourth ]>urt of a 

 peck ; in liquid measure it in the fourth juirt of a 

 pint, and ao synonymous with the im)>cnal gill. A 

 quartern loaf generally weighs 4 ll>. 



Quarter Sessions, a court of Justices of the 

 Peace (q.v.) established in 1350-51, and mating 

 once a quarter. Most of their ailininiatrative duties 

 were in 1888 transferred to the County Councils 

 (nee COUNTY). 



Quarter-stair, once a favourite weapon 

 with tin- BngHah for hand-to-hand encounters, 

 iiinl still sometime* used in athletic exercises, is a 

 Btout pole of heavy wood, al>out 6i feet long, 

 often IxHinil with iron at Imth ends. It i- grMpM 

 in the middle by one hand, the other holding half- 

 way between the middle and end ( hence amuirently 

 the name ' qwurtor-cteff') ; and the attack is made 

 l>y giving it a rapid circular motion, which brings 

 toe loaded emit* on the adversary at unexpected 

 points. See Broadsword atut Singlestick, by 

 Allanson Winn and 1'hillipps \Volley (1890). 



Qliartett, a ]iiece of music arranged for four 

 solo voices or instrument*, in which all the parts 

 are obligate i.e. no one can be omitted without 

 injuring the projier effect of the composition. A 

 mere interchange of melody, by which the parte 

 become in t urn principal and subordinate, without 

 any interweaving of them, does not constitute a 

 qnartett. Quartette for stringed instruments are 

 generally arranged for two violins, viola, and 

 violoncello, and are in sonata form. They origin- 

 ated with Haydn, and were further developed by 

 Mozart, and notably by Beethoven, who perfected 

 the art of part- writ ing. Subsequent writers are 

 Schubert, Spoil r, Mendelssohn, Schumann, and 

 Brahms. Vocal quartetts are a frequent feature in 

 oratorios and operas, up to the time of Wagner. 



Qiiartoderimans. See EASTER. 



QlinrtZ, a mineral composed of silica, Si(( 2 . 

 It is met with chemically pure, but not infre- 

 quently contains variable proportions of ferric 

 oxide, manganese oxides, alumina, magnesia, 

 jime, organic matter, &c. Very often it shows 

 inclusions, microscopic or macroscopic as the case 

 may lie, of various minerals and fluid cavities. It 

 occurs both in crystals ami massive, the more 

 common crystals being hexagonal prisms termin- 

 ated by hexagonal pyramids. Double hexagonal 

 pyramids are also not uncommon. It scratches 

 glass easily, and becomes positively electrical by 

 friction two pieces rubbed together giving light 

 in the dark. Quartz when pure is colourless, but, 

 owing to the presence of foreign snlistances, many 

 coloured varieties are known. Three types of 

 uiirt / are recogn ised : ( 1 ) Rock-rryital, ( 2 ) Cummon 



utirlz, and (3) t'oni/Mtrt Quart;. 



Itnrk cryttnl. Under this head are included the 

 varieties which are more or less transparent and 

 u-siime well-marked crystalline forms. The water- 

 i-lenr crystals are known as Rock-crystal. The 

 crystals are sometimes slender, crossing and pene- 

 trating each oilier in exquisite groups. They 

 frequently enclose other substances, which are 

 beautifully seen through the transparent rock- 

 crystal, as slender hair like or needle-like crystals 

 of hornblende, asbestos, oxiile of iron, rutile or 

 oxide of titanium, oxide of manganese. &c.., and 

 such specimens are known by various fanciful 

 names, as Thetis' Ifair-ttone, Venus' Ilairstour, 

 Venut Pencil*, Cupia"n \ft, Cupid** Arroin. \,-. ; 

 and sometimes the enclosed substAnccs are small 

 Hpangh-H of iron glance, or crystals of iron pyrites. 

 or native silver in fern like leaves, or spangles of 

 gold. Fluid inclusions are also not uncommon, as 

 in the quartz of I'oretta. Very large crystals of 

 perfectly pure rock-crystal are 'sometimes found. 



I 



One from the Alps, which was among the treasure* 

 carried from Italy by the 1-icnch in 17!7, is 3 feet 

 in length, about 1} feet in diameter, and weighs 7 

 cwt. Similar giant crystals are obtained in Mada- 

 gascar. Kock -crystal was prized by the ancients, 

 ami was used by them, as it still is, for vases, cups, 

 seals, &c. An important modern use of it is lor 

 lenses of spectacles, &c., its hardness rendering 

 it much less liable to be scratched than glass. 

 Lenses of rock-crystal are often called Pebble 

 lenses. Rock-crystal is best derelotied in the 

 crevices and cavities of crystalline schistose mid 

 granitoid rocks, such as those of Tyrol and 

 the Alps, where it is associated with felspar, 

 titanitc, rutile, mica, chlorite, and other crystal! is. <1 

 minerals. Smoky Quartz, smoky-brown ; Cairn- 

 gorm, smoky-yellow ; and Morion, black, are 

 varieties the colours of which have been variously 

 attributed to the presence of small quantities of 

 oxide of iron or manganese, or titanic acid or 

 organic substance. Yellow and pellucid varieties of 

 rock -crystal are known as False Topaz. Amethyst 

 (q.v.) or Amethystine Quartz is purple or violet; 

 the darker shades are often highly pi i/ed ; some- 

 times speckled varieties of this U-uutituI mineral 

 occur. When subjected to heat amethyst loses its 

 violet colour and becomes yellow. The Gold Topa* 

 and Citrin of jewellers are in most cases amethysts 

 which have been treated in this way. 



Common Quartz includes non-transparent varie- 

 ties, some of which, however, are more or less 

 translucent. They are either white, colourless, or 

 coloured, the tints being generally pale, but many 

 show intense shades of red, green, yellow, brown, 

 &c. Sometimes they assume crystalline forms, at 

 other times they have a granular or massive struc- 

 ture. The following are varieties : Milk-quart:, 

 milk-white and slightly opalescent (Greenland, 

 &c. ) ; Greasy Quartz, like milk-quartz, but with a 

 greasy lustre ; Rose-quartz, rose-red, sometimes 

 crimson, the colour fading on exposure ( lioden- 

 maisi; Siderite or Sapphire-quartz, indigo or blue 

 in colour, from the presence of asliestos like fibres 

 of blue crocidolite ((lolling in Salzburg): Ferrmjin- 

 oils Quartz, coloured red with ferric oxide or brown 

 with hydrous ferric oxide ; Prase, leek and other 

 shades of green, which are due to needles of actino- 

 lite ( Saxony, &e. ); Star-quart:, containing within 

 the crystal whitish or coloured eccentric radia- 

 tions (Bohemia); Fibroin Quart:, brown, with a 

 silky lustre, psendomorplmus after crocidolite 

 (Cape of Good Hope) ; Quartz-pisolite is an oolitic 

 aggregate of quartz granules (Sicily. Kgypt); 

 h'liiatsttme, porous, cavernous, which lloats in water 

 until the air in its numerous ca\ i ties becomes dis- 

 placed (Cornwall, &c.) ; Cat's-eye, yellow or green- 

 ish, exhibits opalescence, but without prismatic 

 colours, an effect due to fibres of aslicstos or minute 

 tubes arranged in parallel directions (Ceylon, 

 Harz, Fichtelgebirge, &c.). 



Compact Quart: embraces compact and also 

 finely granular aggregates, which are only trans- 

 lucent on their edges. Varieties are llortixtone, 

 gray, brown, yellow, or red, common in many 

 countries; Chrynoprase, a hoi nstone coloured green 

 with nickel (Silesia); Arciiturim- (<|.v.), a some- 

 what granular liornstpne, spangled with scales of 

 mica or goethite( Altai Mountains); Jnxprr (<(.v.(, 

 brown, yellow, red. very impure', with a consider- 

 able percentage of iron. 



Another group of minerals which are included in 

 the quartz family are the chalcedonies. These are 

 mixtures of crystalline and amorphous silica. 

 I'lialredony (q.v.) itself is colourless or pale gray, 

 or pale bluish or yellowish, translucent to semi- 

 opaque, and occurs" either in irregular layers or in 

 mammillary, botrvoidal, or stalactilic forms. The 

 following are coloured chalcedonies : Carnelian, 



