under SPAIN
(q.v.). At the height of its power under James I. (1213-1276), the
kingdom included Valencia, Catalonia, the Balearic Islands and the
considerable territory of Montpellier in France; while Peter III.
(1276-1285) added Sicily to his dominions.

The literature relating to Aragon is very extensive. See, in addition
to the works cited in the article SPAIN (section _History_), "Les
Archives d'Aragon et de Navarre," by L. Cadier, in _Bibliotheque de
l'Ecole des Chartes_, 49 (Paris, 1888). Among the more important
original authorities, the following may be selected:--for general
history, _Anales de la corona de Aragon_, by G. Curita, 3rd ed. in 7
folio volumes (Saragossa, 1668-1671; 1st ed. 1562-1580);--for
ecclesiastical history, _Teatro historico de las iglesias de Aragon_
(Pamplona, 1770-1807); for economic history, _Historia de la economia
politica de Aragon_, by I.J. de Asso y del Rio (Saragossa, 1798). For
the constitution and laws of Aragon, see _Origines del Justicia de
Aragon_, &c., by J. Ribera Tarrago (Saragossa, 1897), and
_Instituciones y reyes de Aragon_, by V. Balaguer (Madrid, 1896). The
topography, inhabitants, art, products, &c., of the kingdom are
described in a volume of the series _Espana_ entitled _Aragon_, by
J.M. Quadrado (Barcelona, 1886).

ARAGONITE, one of the mineral forms of calcium carbonate (CaCO3), the
other form being the more common mineral calcite. It crystallizes in the
orthorhombic system, and the crystals are either prismatic or acicular
in habit. Simple crystals are, however, rare; twinning on the prism
planes (_M_ in the figures) being a characteristic feature of the
mineral (fig. 1). This twinning is usually often repeated on the same
plane (fig. 2), and gives rise to striations on the terminal faces (k)
of the crystals; often, also, three crystals are twinned together on two
of the prism planes of one of them, producing an apparently hexagonal
prism. The mineral is colourless, white or yellowish, transparent or
translucent, has a vitreous lustre, and, in fact, is not unlike calcite
in general appearance. It may, however, always be readily distinguished
from calcite by the absence of any marked cleavage, and by its greater
hardness (H. = 3-1/2-4) and specific gravity (2.93); further, it is
optically biaxial, whilst calcite is uniaxial. It is brittle and has a
subconchoidal fracture; on a fractured surface the lustre is decidedly
resin