from the lead mines near
Dufton in Westmorland. It is found also in beds of iron ore, and the
haematite mines of the Cleator Moor district in west Cumberland have
yielded many extremely fine crystals, specimens of which may be seen in all
mineral collections. In the neighbourhood of Nottingham, and other places
in the Midlands, barytes forms a cementing material in the Triassic
sandstones; amber-coloured crystals of the same mineral are found in the
fuller's earth at Nutfield in Surrey; and the septarian nodules in London
Clay contain crystals of barytes as well as of calcite. Crystals are found
as a rarity in the amygdaloidal cavities of igneous rocks.

Artificially prepared crystals of barytes may be obtained by allowing a
solution of a soluble barium salt to diffuse slowly into a solution of a
soluble sulphate. Barium chloride is present in some natural waters, and
when this is the case the interaction of sulphates results in a deposition
of barytes, as has occurred in the pipes and water-boxes of the
Newcastle-on-Tyne coal mines.

Commercially, barytes is used in the preparation of barium compounds, as a
body for certain kinds of paper and cloth, and as a white pigment
("permanent white"). The finely powdered and washed mineral is too
crystalline and consequently of insufficient opacity to be used alone as a
paint, and is therefore mixed with "white lead," of which material it is
also used as an adulterant.

(L. J. S.)

[Illustration]

BARYTOCALCITE, a rare mineral found only at Alston Moor in Cumberland,
where it occurs as diverging groups of white transparent crystals lining
cavities in the Mountain Limestone. [v.03 p.0457] The crystals belong to
the monoclinic system and are usually prismatic or blade-shaped in habit.
The hardness is 4, and the sp. gr. 3.65. There are perfect cleavages
parallel to the prism faces inclined at an angle of 73deg 6', and a less
perfect cleavage parallel to the basal plane, the angle between which and
the prism faces is 77deg 6'; the angles between these three cleavages thus
approximate to the angles (74deg 55') between the three cleavages of
calcite, and there are other points of superficial resemblance between
these two minerals. Chemically, barytocalcite is a double salt of barium
and calcium carbonates, BaCa(CO_3)_2, thus differing from the orthorhombic
bromlite (_q.v._) which is an isomorphous mixture of the two carbonates.

(L. J. S.)

BARYTONE, or BARITONE (Ital. _bari