See also:

• PICRITE (from Gr. 7rsKpos, bitter, because these rocks are rich in magnesia, a base which forms bitter salts)

PICRITE (from Gr. 7rsKpos, See also:

• BITTER, KARL THEODORE FRANCIS (1867– )

bitter, because these rocks are See also:

• RICH, BARNABE (c. 1540-1617)
• RICH, CLAUDIUS JAMES (1787-1821)
• RICH, JOHN (1692-1761)
• RICH, PENELOPE, LADY (c. 1562–1607)
• RICH, RICHARD, 1ST BARON RICH (1490?-1567)

rich in See also:

• MAGNESIA

magnesia, a See also:

• BASE

base which forms bitter salts)  , a See also:

• ROCK
• ROCK (O.Fr. rake, Sp. rota, Ital. rocca; possibly from a Lat. form rupica, from rupes, rock)
• ROCK, DANIEL (1799–187t)

rock belonging to the ultrabasic See also:

• GROUP

group, and consisting mainly of See also:

• OLIVINE

olivine and See also:

• AUGITE

augite often with See also:

• HORNBLENDE

hornblende and See also:

• BIOTITE

biotite and a greater or less amount of See also:

• PLAGIOCLASE

plagioclase See also:

• FELSPAR, or FELDSPAR

felspar . The picrites are of " hypabyssal " origin and in their natural occurrence are connected with dolerites (diabases and teschenites) . The distinction between them and the peridotites, which have an essentially similar See also:

• COMPOSITION
• COMPOSITION (Lat. compositio, from componere, to put together)

composition, is not easy to define, but the peridotites accompany the true plutonic rocks, such as See also:

• GABBRO

gabbro, norite and See also:

• PYROXENITE

pyroxenite, are often very coarsely crystalline, and See also:

• FORM (Lat. forma)

form large bosses and laccolites, while the picrites usually are found in sills or intrusive sheets . In See also:

• HAND
• HAND (a word common to Teutonic languages; cf. Ger. Hand, Goth. handus)
• HAND, FERDINAND GOTTHELF (1786-185r)

hand specimens the picrites are dark See also:

• GREEN, A
• GREEN, ALEXANDER HENRY (1832—1896)
• GREEN, DUFF (1791—1875)
• GREEN, JOHN RICHARD (1837—1883)
• GREEN, MATTHEW (1696-1737)
• GREEN, THOMAS HILL (1836-1882)
• GREEN, VALENTINE (1739–1813)
• GREEN, WILLIAM HENRY (.1825–1900)

green to See also:

• BLACK
• BLACK, ADAM (1784-1874)
• BLACK, JEREMIAH SULLIVAN (1810–1883)
• BLACK, WILLIAM (1841-1898)

black; the See also:

• ABSENCE (Lat. absentia)

absence or scarcity of See also:

• LATH (0. Eng. laett, Mid. Eng. lappe, a form possibly due to the Welsh llath; the word appears in many Teutonic languages, cf. Dutch lat, Ger. Latte, and has passed into Romanic, cf. Ital. latta, Fr. latte)

lath-shaped plagioclase felspars distinguishes them from diabases and they rarely have the lustre-mottling which is a characteristic of the peridotites . Since they contain much olivine they readily decompose, passing into deep green and See also:

• BROWN
• BROWN, CHARLES BROCKDEN (1771-181o)
• BROWN, FORD MADOX (1821-1893)
• BROWN, FRANCIS (1849- )
• BROWN, GEORGE (1818-188o)
• BROWN, HENRY KIRKE (1814-1886)
• BROWN, JACOB (1775–1828)
• BROWN, JOHN (1715–1766)
• BROWN, JOHN (1722-1787)
• BROWN, JOHN (1735–1788)
• BROWN, JOHN (1784–1858)
• BROWN, JOHN (1800-1859)
• BROWN, JOHN (1810—1882)
• BROWN, JOHN GEORGE (1831— )
• BROWN, ROBERT (1773-1858)
• BROWN, SAMUEL MORISON (1817—1856)
• BROWN, SIR GEORGE (1790-1865)
• BROWN, SIR JOHN (1816-1896)
• BROWN, SIR WILLIAM, BART
• BROWN, THOMAS (1663-1704)
• BROWN, THOMAS (1778-1820)
• BROWN, THOMAS EDWARD (1830-1897)
• BROWN, WILLIAM LAURENCE (1755–1830)

brown incoherent masses in which are embedded rounded lumps of harder consistency . They have a high specific gravity (about 3.0) and may be distinctly magnetic, because they are See also:

• RICH, BARNABE (c. 1540-1617)
• RICH, CLAUDIUS JAMES (1787-1821)
• RICH, JOHN (1692-1761)
• RICH, PENELOPE, LADY (c. 1562–1607)
• RICH, RICHARD, 1ST BARON RICH (1490?-1567)

rich in See also:

• IRON [symbol Fe, atomic weight 55.85 (0=16)]

iron ores . Porphyritic structure is rare though occurring sometimes in the rocks known as See also:

• PICRITE (from Gr. 7rsKpos, bitter, because these rocks are rich in magnesia, a base which forms bitter salts)

picrite-porphyrites; the phenocrysts are olivine and augite . There is seldom any See also:

• FINE

fine-grained or glassy groundmass, and the typical micro-structure is holocrystalline, moderately fine grained and some-what poikilitic . Olivine is abundant in rounded See also:

• PALE (through Fr. pal, from Lat. palms, a stake, for paglus, from the stem pag- of pangere, to fix; " pole " is from the same original source)

pale green crystals . It may form one See also:

• HALF

half of the rock but rarely more than this . The augite is generally brown or reddish-brown, sometimes See also:

• VIOLET

violet, and tends to enclose the olivine, yielding poecilitic aggregates . Brown hornblende often occurs as marginal growths around the See also:

• PYROXENE

pyroxene, and may be so abundant as to replace augite to a large extent; rocks of this class are known as hornblende-picrites .

See also:

• BRIGHT, JOHN (1811-188g)
• BRIGHT, SIR CHARLES TILSTON

Bright green or pale-green hornblende are less frequently See also:

• PRESENT

present, and in many cases are really of secondary origin . Deep brown biotite is a frequent See also:

• ACCESSORY

accessory See also:

• MINERAL

mineral and both biotite and hornblende sometimes enclose olivine . A small amount of basic plagioclase occurs in many picrites; See also:

• APATITE

apatite, iron oxides, See also:

• CHROMITE

chromite and spinels are See also:

• MINOR
• MINOR (Lat. for smaller, lesser)
• MINOR, ROBERT CRANNELL (1839-1904)

minor ingredients I seldom altogether absent . The minerals of picrites are very frequently decomposed . See also:

• SERPENTINE

Serpentine partly or wholly replaces olivine, forming radiate fibrous masses which are green, yellow or red in microscopic sections . Sometimes hornblende (pilite), See also:

• TALC

talc, See also:

• CHLORITE

chlorite and See also:

• MICA

mica appear as secondary products after olivine . The augite passes into chlorite or into green fibrous or platy See also:

• AMPHIBOLE

amphibole . Hornblende and biotite are often fresh when the other components are much altered . The felspar is rarely in See also:

• GOOD, JOHN MASON (1764-1827)

good preservation but yields See also:

• EPIDOTE

epidote, See also:

• PREHNITE

prehnite, sericite, See also:

• KAOLIN

kaolin; See also:

• CALCITE

calcite and See also:

• ANALCITE

analcite are abundant in some weathered picrites . Rocks of this type are well represented in See also:

• GREAT

Great See also:

• BRITAIN (Gr. Hperavuml vi7vot, Bperravia; Lat. Britannia, rarely Britannia)

Britain . In the central valley of See also:

• SCOTLAND
• SCOTLAND, CHURCH OF
• SCOTLAND, EPISCOPAL CHURCH OF

Scotland several masses of picrite have been discovered, always in See also:

• CLOSE
• CLOSE (from Lat. clausum, shut)
• CLOSE, MAXWELL HENRY (1822-1903)

close association with olivine-See also:

• DIABASE

diabase and teschenite . One of these forms the See also:

• ISLAND (O.E. ieg =isle, +land')

island of Inchcolm in the See also:

• FIRTH, CHARLES HARDING (1857– )
• FIRTH, MARK (1819-1880)

Firth of Forth, another lies near See also:

• BATHGATE

Bathgate (in See also:

• LINLITHGOWSHIRE, or WEST LOTHIAN

Linlithgowshire), and there are others at See also:

• ABERDOUR

Aberdour (See also:

• FIFE
• FIFE (Fr. fifre; Med. Ger. Schweizerpfeiff, Feldpfeiff; Ital. ottavino)

Fife), See also:

• ARDROSSAN

Ardrossan and Barnton (Midlothian) .

They belong to the great See also:

• SERIES (a Latin word from serere, to join)

series of Carboniferous eruptive rocks of the Scottish midland valley . These picrites are not known to be represented in See also:

• ENGLAND
• ENGLAND, THE CHURCH OF

England, but, on the other hand, there are Devonian picrites in See also:

• DEVON, EARLS OF

Devon and See also:

• CORNWALL

Cornwall as basic members of the diabase and proterobase series of these counties . Some of them contain much augite like the picrite (often called palaeopicrite as being of palaeozoic See also:

• AGE (Fr. age, through late Lat. aetaticum, from aetas)

age) at Menheniot Station in Cornwall and the picrite of Highweek near See also:

• NEWTON
• NEWTON, ALFRED (1829–1907)
• NEWTON, JOHN (1725-1807)
• NEWTON, JOHN (1823-1895)
• NEWTON, SIR CHARLES THOMAS (1816-1894)
• NEWTON, SIR ISAAC (1642-1727)

Newton See also:

• ABBOT (from the Hebrew ab, a father, through the Syriac abba, Lat. abbas, gen. abbatis, O.E. abbad, fr. late Lat. form abbad-em changed in 13th century under influence of the Lat. form to abbat, used alternatively till the end of the 17th century; Ger. Ab
• ABBOT, EZRA (1819-1884)
• ABBOT, GEORGE (1603-1648)
• ABBOT, ROBERT (1588?–1662?)
• ABBOT, WILLIAM (1798-1843)

Abbot in See also:

• DEVONSHIRE (DEvoN)
• DEVONSHIRE, EARLS AND DUKES OF

Devonshire . Others are hornblende-picrites like that of Cartuther near St Germans, Cornwall . Hornblende-picrite occurs also in the island of See also:

• SARK

Sark and several beautiful examples have been described from See also:

• ANGLESEY, ARTHUR ANNESLEY
• ANGLESEY, HENRY WILLIAM PAGET
• ANGLESEY, or ANGLESEA

Anglesey and from Penarfynnydd in See also:

• NORTH
• NORTH, BARONS
• NORTH, MARIANNE (1830—1890)
• NORTH, ROGER (1653-1734)
• NORTH, SIR THOMAS (1535?-16o1?)

North See also:

• WALES (Cymru, Gwalia, Cambria)

Wales and from See also:

• WICKLOW

Wicklow in See also:

• IRELAND
• IRELAND, CHURCH
• IRELAND, CHURCH OF
• IRELAND, JOHN (1761-1842)
• IRELAND, JOHN (1838- )
• IRELAND, WILLIAM HENRY (1777-1835)

Ireland . Picrites occur in several parts of See also:

• GERMANY
• GERMANY (Ger. Deutschland)

Germany, notably in the Devonian rocks of the See also:

• FICHTELGEBIRGE

Fichtelgebirge and See also:

• NASSAU

Nassau, where they accompany diabases and proterobases like those of Cornwall and Devonshire . In See also:

• SILESIA

Silesia and See also:

• MORAVIA (Ger., Ma/wen; Czech, Morava)

Moravia picrites are found with teschenites like those of Central Scotland . In some of the See also:

• CONTINENTAL

continental picrites See also:

• ENSTATITE

enstatite is present but is rare . In North See also:

• AMERICA

America picrites occur among the igneous rocks on the See also:

• HUDSON
• HUDSON, GEORGE (180o-1871)
• HUDSON, HENRY
• HUDSON, JOHN (1662–1719)

Hudson See also:

• RIVER

river and in See also:

• ALABAMA

Alabama and See also:

• MONTANA

Montana . (J . S .