French :
Ecume de mer.
Physical and optical
properties :
Colour : white to yellow to yellow-brown
-
Transparency :
opaque
-
Lustre : vitreous
- Hardness : 4
- Density :
-
I. R. : 1.508 – 1.700
-
Birefringence : - 0.192
-
Cleavage : perfect
-
System : trigonal
MAGNESIUM-ZINC-SPINEL :
Synonym of Gahno-spinel
MAGNOCHROMITE :
Synonym of Magnesium-Chromite
MAGOLITE :
Synonym of Soapstone
MALACHITE :
Etym. : from the Greek : malakos = soft stone, or from the Greek
: malache = mallow
CuCo3.Cu(OH)2
Physical and optical properties
- Colour
: green with light green and blackish green zones, banded
- Transparency
: opaque
- Lustre
: dull or silky
- Hardness
: 3.5 to 4
- S.G. :
3.95 (+ 0.15 - 0.70)
- R.I. :
1.660 - 1.910
- Birefringence
: 0.250
- Dispersion
: -
- Biaxial
negative
- Pleochroism
: -
- System : monoclinic
(BLUE)
MALACHITE :
Prohibited
Appellation
for azurite
(COPPER) MALACHITE :
Prohibited
Appellation
for chrysocolla
MALACHITE EMERALD :
Prohibited
Appellation
for dioptase
MALACHIT-JADE :
Prohibited
Appellation
for a green and white marble
MALACHITKIESEL :
German term. Synonym
of Chrysocolla
MALACOLITE :
Variety of Diopside of Sweden of dark to light green
colour, transparent
MALACON :
Zircon, hydrated to 3% with water, isotropic
S.G. : 3.90 to 40
Hardness : 6
MALTESITE :
Variety of Andalousite resembling Chiastolite and originating from Finland
MALVENFARBENERDIAMANT :
German Appellation
Diamond of intensive colour in violet-blue,
red hues.
MANCHURIAN JADE :
Synonym of Agalmatolite (variety of soapstone)
MANDELSTEIN :
German Appellation designating an eruptive rock forming holes serving
subsequently to the formation of Agates
MANGANAMPHIBOLE
:
Synonym of Rhodonite
MANGANESE-GARNET :
Synonym of Spessartite
MANGANKIESEL :
German Name for Rhodonite; or mixture of Quartz and of Rhodochrosite ( Klockmann )
MANGANOANDALOUSlTE :
Variety of Andalousite of grass green colour
MANGANOCALCITE :
Synonym of Rhodochrosite
MANGANOLITE :
Synonym of Rhodonite
MANGANSPINEL :
Synonym of Jacobsite
MAN JADE :
Chinese Name for a Jade of blood red colour
MANSJOITE :
Variety of Diopside rich in fluor, of greyish green
colour and originating in Sweden
MARANITE :
Synonym of Chiastolite
MARATHONSTEIN :
German Appellation ; Synonym of Obsidian
MARBLE VERD-ANTIQUE :
Synonym for : verd-antique
MARCASITE :
See Marcassite
MARCASSITE :
Etym. : from Sanskrit: Makshika = yellow as honey
or from the Arab word : Markaschitsa : fire stone ( this term was before
equally employed for a very scintillating pyrite)
FeS2
Related with Pyrite, but orthorhombic
Physical and optical properties :
- Colour : yellow, yellow grey
- Transparency : opaque
- Lustre : metallic
- Hardness : 6 to 6.5
- S.G. : 4.61 to 4.88
- System : orthorhombic
MAREKANITE :
Variety of Obsidian
from Siberia
Colours :
- brown marbled and black (Merril)
- smoky and cloudy grey (Eppler)
- brown and grey often yellow and red, in part uniform, in part with
varied colours , similar to Mexican material (Schlossmacher )
MARIALlTE :
Variety of sodic Scapolite
(AlSi308)6Na8(Cl2.CO3.S04)
grey, greenish or red
MARI-DIAMOND :
Prohibited
Appellation
for a rock crystal from the lndus region
(India )
MARKASIT :
German Name for Marcassite
MARMAROSCH DIAMOND :
Prohibited
Appellation
English for dragomite
MARMODORA DIAMOND :
Prohibited
Appellation English for a quartz
MARMOLITE
:
Type of Serpentine, variety of chrysotile, composed
for the major part of Chrysotile , and/or Lizardite.
MASCAREIGNITE :
Variety of Opal.
MASCOT EMERALD :
Prohibited
Appellation
(English) ; commercial name for a triplet composed of Beryl imitating emerald
MASS AQUA :
Commercial Name (English) for a crown glass borosilicate serving to imitate
aquamarine
R.I. : 1.50 to 1.51
S.G. : 2.35 to 2.37
Hardness : 6
MASS OPAL :
English Name for Matrix opal
MATARA DIAMOND or MATURA DIAMOND :
Prohibited
Appellation
for a decoloured zircon from the Matara or Matura district, Sri Lanka
(MATRIX) OPAL :
A gemstone showing veins of opal in rocky gangue
MAUILITE :
Variety of Labradorite
MAW-SIT-SIT
:
Burmese Name for a rock composed of very fine mixture of jadeite, kosmochlore,
zeolite, albite and serpentine) of green colour (or seldom mauve), sometimes
with yellowish tones and almost always with black spots. Found on the
plateau of Taw-Maw in Myanmar.
The name of jade-kosmochlore has been
proposed.
S.G. : 2.9
MAXIXE-AQUAMARINE :
Blue Beryl showing a very strong dichroïsm
and coming from the Maxixe mines in the province of Minas Gerais , Brazil
MAXY :
Synonym for Marcassite
MAYAITE :
Variety of diopside-jadeite coming from Central America and
found in the ancient tombs of the Maya
To be classified together with tuxtlite very similar to white to grey, green to yellowish
green Albite .
MEDFORDITE :
Local Name for a white massive Quartz with green or brown lines and spots and coming
from Oregon
MEDINA EMERALD :
Prohibited
Appellation
(English) for a green glass
MEERSCHAUM :
Originally a German Name. Also called sepiolite. In French called Ecume de mer.
A microcrystalline hydrous
magnesium silicate
Because the material is so
porous it floats.
Formed as a decomposition
product of serpentine.
Used for small objects and
cigarette holders /pipes ; in jewellery : used treated (impregnated) with
grease to give it lustre
Mg4 (OH) 2/Si6O15.6H2O
Physical and optical properties:
- Colours : white, grey, yellowish, pink to reddish.
-Transparency
: opaque
- Lustre
: dull
- Hardness : 2 to 2.5
- S.G. : 2
- R.I. : average 1.53
- system : orthorhombic
Occurrences :
Eskischehir (Anatolia,
Turkey)
MEI-KUO LU JADE :
Chinese Name for a variety of mediocre quality Jade with a light green colour
MEIONITE :
Variety of Scapolite containing calcium
(Al2Si208
)3 . Ca4 . ( Cl2CO3 , SO4)
Colours : blue, green greyish
MEKKASTEIN :
German term; variety of bluish Chalcedony from Arabia
MELANITE :
Etym. : from the Greek melas = black
Variety of garnet andradite containing titanium
Colour : black opaque
Hardness : 6.5
S.G. : 3.77
MELICHRYSOS :
Synonym of Zircon.
MELLOW AMBER :
English Name for Gedanite
MELON D'EAU :
French for Water melon (tourmaline). Variety of Tourmaline : red in the middle encircled by
a green part
MELTING SNOW JADE :
Descriptive English Term, designating a white to greyish Jadeite with opaque spots and translucent
lines
MENAC :
Synonym of Sphene.
MENACANNITE :
Variety of Ilmenite from Menacan in Cornwall, Great
Britain
MENAKERZ :
German term. Synonym of Sphene.
MENILITE or (MENILITE) OPAL :
Common Opal, opaque, with lines, greyish or
brownish in colour
Etym.: from Ménilmontant (France) , where it is found
MESOLITINE :
Synonym of Thomsonite
METAXITE :
Variety of Serpentine from Silesia ( chrysotile )
METEORIC GLASS :
English Name for Moldavite.
MEXICAN AGATE :
Prohibited Appellation (English) a calcite or a banded
aragonite
MEXICAN AMBER :
(English) Synonym for Bacalite
MEXICAN DIAMOND :
Prohibited Appellation (English) for a rock crystal
MEXICAN JADE :
Prohibited Appellation (English) for a common mineral,
generally calcite, tinted green
MEXICAN
ONYX :
Prohibited Appellation (English) for a calcite or a banded
aragonite, of yellowish or greenish colour and coming principally from
Argentine
Prohibited Appellation for an onyx marble .
(MEXICAN) RUBY :
Prohibited
Appellation for a for fire opal of red colour .
(MEXICAN) TURQUOISE :
See
American turquoise .
MICAPHILITE :
Synonym for Andalousite.
MICARTA
:
Plastic material similar to Bakelite
MICHAELITE :
Variety of Opal.
MICROLlNE :
Group of minerals belonging to the family of the Feldspars, of which only the variety of Amazonite is normally used as a gemstone
MICROPHAKITE :
Variety of Labradorite.
MICROSOMMITE :
Variety of Sodalite.
MIDGE STONE :
Synonym for gnat stone
(English)
MIJRIKITE :
Cinabar included in Chalcedony of
amber colour
MIKIMOTO PEARLS :
Commercial Name for the cultured pearls from Japan produced and controlled
by Mikimoto Company
MILK
OPAL or (MILKY) OPAL :
English Name for an opal with
a hazy or creamy milky appearance
MILKY JASPER :
English Name for white Jasper ( Eppler )
MILKY QUARTZ :
English Name for a variety of Quartz, white, opaque to slightly translucent , sometimes
containing very small particles of gold and therefore called "
gold quartz "
MIROIR
DES INCAS :
French. Name sometimes given to Obsidian (because the Incas and Pre-Columbian Indians
made flat slabs out of this material which once polished were used as
mirors)
MITCHELLITE :
Synonym of Magnesiochromite
MIZZONITE
:
Variety of Scapolite generally considered as noble scapolite
Colours : yellow, pink
MOCHA PEBBLE :
(English) term. See mocha stone.
MOCHA STONE :
Variety of brown Moss agate
from Arabia ; in reality moss agate is not an agate but a Chalcedony
;
Crypto-crystalline Quartz, translucent white,
grey or yellowish having inclusions of iron of brown to red colour and
dendritic inclusions of black manganese
For several localities in the N-W of the
U.S.A., synonym of landscape-agate. For the non gemmologist, no distinction
is made between mocha stone and moss agate
MOGOK-DIAMOND :
Prohibited Appellation for a colourless topaz from
Mogok (Myan Mar)
MOHAVE MOONSTONE :
Prohibited Appellation for a chalcedony of lilac colour
coming from the Mohave desert, in California
MOISSANITE :
Rare natural mineral (mainly from meteoritic origin).
Produced synthetically for industrial
(abrasive) purpose since 1920’s.
Synthetic product imitating diamond.
Silicon Carbide.
SiC
Physical and optical properties :
- Colours : colourless, pale pink-violet (rare), green
- Transparency : transparent
- Hardness : 9.25 to 9.5
- S.G. : 3.2
- R.I. : average : 2.7
- Birefringence : 0.040
- Dispersion : 0.110
- Crystal system : hexagonal, rarely cubic
(produced in cubic form as imitation for diamond)
To
consult absolutely :
MOJAVE MOONSTONE :
Prohibited Appellation for a chalcedony greyish in colour
and translucent ( Pough ), or Synonym of mohave moonstone ( Merrill )
MOKKASTEIN :
German Name for Mocha Stone.
MOLDAVITE :
Etym. from the Moldau ( Ultava ) in former Tchechoslovakia
= a natural meteoritic glass, amorphous
Physical and optical properties :
- Colours : green to brownish green, bottle green, brown, blackish green
- Transparency : transparent to translucent
- Lustre : vitreous
- Hardness : 5,5
- Density : 2.30 to 2.44
- R.I. : 1.48 to 1.55
MOLDED CAMEO :
English term. Imitation of a cameo made in materials such as ceramic
, metal, glass, plastic, wax
MOLLITE :
Synonym of Lazulite.
MONDQUARTZ :
German Name given to a variety of Quartz.
MONDSTEIN :
German Name for Moonstone .
MONEY STONE :
Local Name for Rutile in Pennsylvania
MONGOLITE :
Variety of Jasper.
MONHEIMITE :
Variety of iron containing Smithsonite.
MONTANA AGATE :
Name given to a stone looking like a Mocha Stone in Montana
MONTANA
JET :
Prohibited Appellation for an obsidian from the Yellowstone
Park, USA
MONTANA RUBY :
Prohibited Appellation a pyrope or almandine garnet .
MONT BLANC RUBY :
Prohibited Appellation (French : Rubis du Mont Blanc) for
a rose quartz found on the Mont Blanc, in the Alps, in France
MONTEBRASITE :
LiAl ( OH.PO4
)
The name of montebrasite was first given to a fluor-phosphate of aluminium
of pale green or ash-grey colour, accompanying amblygonite at Montebras
Actually name given to a variety of Amblygonite from Hebron ( United States) of
which a similar variety exists at Montebras
MONZONITE :
Compact variety of Grossular Garnet.
MOONSTONE :
Variety of orthose feldspar, also called adular, in which fine lamellae of albite formed; when cut as a cabochon presenting
the optical effect known under the name of adularescence
(K,Na)A1Si308
Physical and optical properties
:
- Colour : the most appreciated are colourless
and fully transparent displaying a very beautiful bluish reflection,
others are
translucent, milky and pearly or brown-reddish,
creamy, orange, grey-green
- Transparency : transparent to opaque
- Hardness : 6
- Density : 2.54 to 260
- R.I. : 1.532 to 1.542
- Birefringence : 0.008 to 0.010
- System
: monoclinic
(BLACK) MOONSTONE :
See
labradorite from Madagascar .
(MOJAVE) MOONSTONE :
Prohibited Appellation for a tinted chalcedony.
(ORIENTAL) MOONSTONE :
Prohibited Appellation for a girasol sapphire, or term serving to designate the
true moonstone to distinguish it from its imitations ( old appellation) .
(PINK) MOONSTONE :
Prohibited Appellation for a variety of pink opalescent scapolite .
MOONSTONE from CANADA :
Variety of labradorite .
MOONSTONE from CALIFORNIA :
Prohibited Appellation for a chalcedony.
MOONSTONE from ONTARIO :
Variety of peristerite from Ontario, Canada.
MOOR'S HEAD :
English name for a variety of tourmaline with a black coloured termination.
See (French) Tête
de Maure.
MOOSACHAT :
German Name for moss agate .
MOOSSTEIN :
German Name for moss agate .
MORACILLA :
Variety of common Beryl , opaque and white
MORA DIAMOND :
Prohibited Appellation for a colourless stone probably
a rock crystal ( Merrill )
MORALLA : ou MARALLION :
Semi-crystallised material, coming from the Colombian emerald mines
and having the appearance of a green turquoise with matrix ;
or commercial name sometimes employed for designating a quality of emerald
of the poorest quality.
MORGANITE
:
Etym. : named after the American financer: John Pierpont Morgan
Variety of Beryl containing caesium
showing the colours pink, reddish, pink-violet
MORION :
Etym.: from the Greek moreios = dark
A transparent smoky Quartz
of a very dark brown to almost black colour
MORMORION :
Synonym of Morion.
MORNING NEW JADE :
(English) greenish Jade with small scintillating spots
MORNITE :
Variety of iron containing Labradororite
MORO CORAL :
(English) Dark red Coral .
MOROXITE :
Variety of Apatite blue to greenish blue.
MOSAIC AGATE :
Prohibited
Appellation
(English), Synonym of Mexican Agate.
MOSQUITO AMETHYST :
English term. Amethyst
containing very small inclusions of Goethite.
MOSQUITO STONE :
Name given in Spain to a quartz with small dark inclusions, it resembles
a Mocha Stone
MOSS AGATE :
Is actually no agate but a variety of milky chalcedony with moss-like
inclusions of green or rusty brown colour due to chlorite inclusions.
French : agate mousse.
MOSS OPAL :
Milky opal with black inclusions resembling
to moss
MOTHER-OF-EMERALD :
Prohibited Appellation (English) for a green fluorite or
a prase
MOTHER-OF-PEARL :
Carbonate of calcium secreted by the molluscs
and constituting the iridescent part of the shell.
CaCO3
MOTHER-OF-PEARL OPAL :
English Name for Cacholong.
MOTHER 'S GEM :
Name sometimes given in America to a Jade.
MOUNTAIN BLUE :
(English) Synonym of Azurite or Chrysocolla .
MOUNTAIN CRYSTAL :
American Name for Rock crystal.
MOUNTAIN JET :
Prohibited
Appellation (English)
for a black Obsidienne
MOUNTAIN LILY TOPAZ :
Commercial (English) Name for the blue Topaz of superior quality coming from San Diego County
, California
MOUNTAIN MAHOGANY :
(English) Name given by the Americans to a reddish Obsidian
MOUNTAIN RUBY :
Prohibited
Appellation
(English) for a red garnet (‘acajou’ colour)
MOUNTAIN STONE :
English Name sometimes given to Jade.
MULDAN :
Variety of Orthoclase.
MULLER'S GLASS :
(English) Synonym of Hyalite.
MUNTENITE :
Variety of Amber from
Olanesti in Romania
MURCHISONITE :
Variety of Orthoclase.
MURRA : ou MURRHA :
Designates a whole range of Ornamental stones or materials used in ancient
Rome, such as Jadeite, fluorite, porcelain, iridescent glass, or
also an artificially coloured chalcedony
MURRHINA :
Synonym for fluorite.
MURSINKA AQUAMARINE :
Commercial Name for an Aquamarine of light bluish green colour from
Mursinka-Miask in the Ural
MURSINKA TOPAZ :
Commercial Name for a topaz of light blue colour from Mursinka-Miask in
the Urals
MURSINKITE
:
Tetragonal mineral often found as inclusions in topaz (from the Urals).
MUSCOVITE :
Variety of the group of the micas ; it is a quite common mica
Physical and optical properties :
- Colours : colourless, yellowish, brownish, greenish
- Hardness 2 to 2.5
- P.S. : 2,78 to 3.1O
- R.I. : 1.556 to 1.59
MUSSITE :
Synonym of Diopside.
MUTTON
FAT JADE :
Chinese Name designating a variety of white Nephrite resembling to the colour of mutton-grease
MUTZCHEN DIAMOND :
Prohibited Appellation for a rock crystal from Mutzschen
( Saxony ), Germany
MAY
YAY :
Burmese Term serving to designate a translucent uniformly grass-green
Jade of superior quality
MYRIKITE :
Name given to a Chalcedony whitish
and greyish, or to an Opal of the same colour, or to a massive quartz
containing rosy or reddish inclusions of cinnabar but having a general
brownish aspect
For the English it is a variety of grey chalcedony with red spots resembling
to "Saint Stephen's stone".
MYRMEKITE :
Mixture of Quartz and feldspar.
