MAGNESITE
Rarely in clear facetable crystals from Brazil providing gems to 15 ct. for collectors.
Brazil, colorless, to 50 gm.+ gm. .75-1.50
MAGNETITE
Black magnetic iron ore sometimes cut as a curiosity.
MALACHITE
Bright green copper carbonate known from antiquity and extensively used for ornamental items and carvings, and for beads and other forms of jewelry; soft but dense and fairly tough in thick sections; attractively banded in shades of dark to pale green, the darker material accepting a better polish; often in large masses to many pounds in weight but seldom thicker than 4″ with usual crusts being 1″—2″ thick; slowly alters to a black coating, especially if exces¬sively handled; classic sources in Russia exhausted; sporadic production from Arizona; principally supplied from copper mines in Africa.
MARCASITE
Bright metallic luster similar to pyrite and formerly used for small faceted gems to ornament buckles but now superseded by similar gems cut from stain¬less steels.
MARCASITE AGATE, See QUARTZ MARIPOSITE
Foliated rock with bright green streaks of fuchsite mica in white ground mass; soft; suitable for ornamental objects.
MEERSCHAUM, see SEPIOLITE MESOLITE
White fibrous zeolite mineral sometimes cut into chatoyant cabochons; soft; collectors’ item only.
Oregon, pieces to 2″ lb. 2.00
METEORITES
Metallic meteorites are occasionally sliced and polished for unusual jewelry; very small “nuggets” have been set whole in tie clasps.
MICROCLINE, see FELDSPAR MICROLITE
Extremely rare in facet-grade crystals which come only from the Rutherford mines near Amelia, Virginia; dark reddish-brown to pale brown; cut gems not over 3 ct.
Virginia, to 5 ct. ct. 5.00-10.00
MIMETITE
Compact forms of this lead mineral have been cut into bright orange cabo¬chons; soft; collectors’ curiosity; occasionally available from Mexico.
MOLDAVITE, See TEKTITE MOONSTONE, See FELDSPAR MORDENITE
White fibrous zeolite mineral from Nova Scotia; sometimes cut into cabochons showing weak chatoyancy.
Nova Scotia, nodules up to s/^” ea. .25-.50
MORGANITE, See BERYL
MORION, See QUARTZ
MOTHER OF PEARL, See SHELL
MOZARKITE, See QUARTZ (CHERT and FLINT)
MUSCOVITE
Massive, fine-grained rose material from New Mexico has sometimes been cut into cabochons; soft; collectors’ item only.
I
MYRICKITE, See OPAL NACRE, see SHELL NATROLITE
Colorless slender crystals of this zeolite mineral provide very small facetec eems; largest arenas to 2 ct. have been cut from California material.