ANDALUSITE  , a See also:

• MINERAL

mineral with the same chemical See also:

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

composition as See also:

• CYANITE

cyanite and See also:

• SILLIMANITE

sillimanite, being a basic See also:

• ALUMINIUM (symbol Al; atomic weight 27.0)

aluminium silicate, Al2SiO5 . As in sillimanite, its crystalline See also:

• FORM (Lat. forma)

form is referable to the orthorhombic See also:

• SYSTEM

system . Crystals of andalusite have the form of almost square prisms, the See also:

• PRISM (Gr. rrpivµa, properly a thing sawn, Irpii"ety, to saw)

prism-See also:

• ANGLE (from the Lat. angulus, a corner, a diminutive, of which the primitive form, angus, does not occur in Latin; cognate are the Lat. angere, to compress into a bend or to strangle, and the Gr. ayKOS, a bend; both connected with the Aryan root ank-, to

angle being 89° 12'; they are terminated by a basal See also:

• PLANE

plane and some-times by small See also:

• DOME (Lat domus, house; Ital. duomo, cathedral)

dome-faces . As a See also:

• RULE

rule the crystals are roughly See also:

• DEVELOPED

developed and See also:

• RUDE, FRANCOIS (1784–1855)

rude columnar masses are See also:

• COMMON

common, these being frequently altered partially to See also:

• KAOLIN

kaolin or See also:

• MICA

mica . Such crystals, opaque, and of a greyish or brownish See also:

• COLOUR (Lat. color, connected with celare, to hide, the root meaning, therefore, being that of a covering)

colour, occur abundantly in the mica-schist of the Lisens See also:

• ALP

Alp near See also:

• INNSBRUCK

Innsbruck in See also:

• TIROL (or TYROL 1)

Tirol, while the first noted of the many localities of the mineral is in See also:

• ANDALUSIA, or ANDALUCIA

Andalusia, from which See also:

• PLACE (through Fr. from Lat. platea, street; Gr. IrAar6s, wide)

place the mineral derives its name . The unaltered mineral is found as transparent pebbles with See also:

• TOPAZ

topaz in the See also:

• GEM (Lat. gemma, a bud,—from the root gen, meaning " to produce,"—or precious stone; in the latter sense the Greek term is > d>os)
• GEM, ARTIFICIAL

gem-gravels of the See also:

• MINAS [MINOIDES] (c. 1790-186o)

Minas Novas See also:

• DISTRICT

district, in Minas Geraes, See also:

• BRAZIL
• BRAZIL, or BRASIL

Brazil . These pebbles are usually 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 but sometimes reddish-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 in colour, and are remarkable for their very strong dichroism, the same pebble appearing green or reddish-brown according to the direction in which it is viewed . Such specimens make very effective gem-stones, the degree of hardness of the mineral (H . = 71) being quite sufficient for this purpose . Its specific gravity is 3.18; it is unattacked by acids and is infusible before the See also:

• BLOWPIPE

blowpipe . Andalusite is typically a mineral of metamorphic origin, occurring most fre- quently in altered See also:

• CLAY (from O. Eng. claeg, a word common in various forms to Teutonic languages, cf. Ger. Klei)
• CLAY, CASSIUS MARCELLUS (1810-1903)
• CLAY, CHARLES (1801–1893)
• CLAY, FREDERIC (1838–1889)
• CLAY, HENRY (1777–1852)

clay-slates and crystalline See also:

• SCHISTS (Gr. vxq'ecv, to split)

schists, near the junction of these with masses of intrusive igneous rocks such as See also:

• GRANITE (adapted from the Ital. granite, grained; Lat. granum, grain)

granite . It has been recognized also, however, as a See also:

• PRIMARY

primary constituent of granite itself .

A curious variety of andalusite known as chiastolite is specially characteristic of clay-slates near a contact with granite . The elongated prismatic crystals enclose symmetrically arranged wedges of carbonaceous material, and in See also:

• CROSS

cross-See also:

• SECTION
• SECTION (Lat. sectio, cutting, secare, to cut)

section show a See also:

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

black cross on a greyish ground . Cross-sections of such crystals are polished and worn as amulets or charms . Crystals of a See also:

• SIZE

size suitable for this purpose are found in See also:

• BRITTANY

Brittany and the See also:

• PYRENEES [Span. Pirineos, Fr. Pyrenees]

Pyrenees, while still larger specimens have been found recently in See also:

• SOUTH
• SOUTH, ROBERT (1634–1716)

South See also:

• AUSTRALIA

Australia . The name chiastolite is derived from the See also:

• GREEK
• GREEK, ETRUSCAN AND

Greek xraoros, crossed or marked with the See also:

• LETTER (through Fr. lettre from Lat. littera or litera, letter of the alphabet; the origin of the Latin word is obscure; it has probably no connexion with the root of linere, to smear, i.e. with wax, for an inscription with a stilus)

letter x: cross-See also:

• STONE
• STONE (0. Eng. shin; the word is common to Teutonic languages, cf. Ger. Stein, Du. steen, Dan. and Swed. sten; the root is also seen in Gr. aria, pebble)
• STONE, CHARLES POMEROY (1824-1887)
• STONE, EDWARD JAMES (1831-1897)
• STONE, FRANK (1800-1859)
• STONE, GEORGE (1708—1764)
• STONE, LUCY [BLACKWELL] (1818-1893)
• STONE, MARCUS (184o— )
• STONE, NICHOLAS (1586-1647)

stone and made are earlier names, the latter having been given on See also:

• ACCOUNT
• ACCOUNT (through O. Fr. acont, Late Lat. comptum, cornputare, to calculate)

account of the resemblance the cross-section of the stone bears to the heraldic macula or mascle . (L . J .