LEADHILLITE  , a rare See also:

• MINERAL

mineral consisting of basic See also:

• LEAD
• LEAD (pronounced iced)

lead sulphatocarbonate, Pb4 SO4 (CO3)2(OH)2 . Crystals have usually the See also:

• FORM (Lat. forma)

form of six-sided plates (fig . 1) or sometimes of acute rhombohedra (fig . 2); they have a perfect basal cleavage (parallel to P in fig . I) on which the lustre is strongly pearly; they are usually See also:

• WHITE
• WHITE, ANDREW DICKSON (1832– )
• WHITE, GILBERT (1720–1793)
• WHITE, HENRY KIRKE (1785-1806)
• WHITE, HUGH LAWSON (1773-1840)
• WHITE, JOSEPH BLANCO (1775-1841)
• WHITE, RICHARD GRANT (1822-1885)
• WHITE, ROBERT (1645-1704)
• WHITE, SIR GEORGE STUART (1835– )
• WHITE, SIR THOMAS (1492-1567)
• WHITE, SIR WILLIAM ARTHUR (1824--1891)
• WHITE, SIR WILLIAM HENRY (1845– )
• WHITE, THOMAS (1628-1698)
• WHITE, THOMAS (c. 1550-1624)

white and translucent . The hardness is 2.5 and the sp. gr . 6.26-6.44 . The crystallographic and See also:

• OPTICAL

optical characters point to the existence of three distinct kinds of leadhillite, which are, however, identical in See also:

• EXTERNAL

external See also:

• APPEARANCE (from Lat. apparere, to appear)

appearance and may even occur intergrown together in the same crystal: (a) See also:

• MONOCLINIC

monoclinic with an optic axial 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 of 200; (b) See also:

• RHOMBOHEDRAL

rhombohedral (fig . 2) and optically uniaxial; (c) orthorhombic (fig . I) with an optic axial angle of 721° . The first of these is the more See also:

• COMMON

common See also:

• KIND (O. E. ge-cynde, from the same root as is seen in " kin," supra)

kind, and the second has See also:

• LONG, GEORGE (1800-1879)
• LONG, JOHN DAVIS (1838– )

long been known under the name susannite . Tits fact that the published analyses of leadhillite vary somewhat from the See also:

• FORMULA
• FORMULA (Lat. diminutive of forma, shape, pattern, &c., especially used of rules of judicial procedure)

formula given above suggests that these three kinds may also be chemically distinct .

Leadhillite is a mineral of secondary origin, occurring with See also:

• CERUSSITE

cerussite, anglesite, &c., in the oxidized portions of lead-bearing lodes; it has also been found in weathered lead slags See also:

• LEFT

left by the See also:

• ROMANS
• ROMANS, EPISTLE TO THE

Romans . It has been found most abundantly in the Susanna mine at See also:

• LEADHILLS

Leadhills in See also:

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

Scotland (hence the names leadhillite and susannite) . See also:

• GOOD, JOHN MASON (1764-1827)

Good crystals have also been found at Red Gill in See also:

• CUMBERLAND
• CUMBERLAND, DUKES AND EARLS OF
• CUMBERLAND, RICHARD (1632-1718)
• CUMBERLAND, RICHARD (1732-1811)
• CUMBERLAND, WILLIAM AUGUSTUS

Cumberland and at See also:

• GRANBY, JOHN MANNERS, MARQUESS

Granby in See also:

• MISSOURI

Missouri . Crystals from See also:

• SARDINIA (Gr. 'IXs'o"uva, from a fancied resemblance to a footprint in its shape, Ital. Sardegna)

Sardinia have been called maxite . (L . J .