BOART :
Synonym : Boort or Bort.
Impure industrial diamond, mostly in the form of rough spheroids.
Physical and optical properties :
- Colour :, white-grey to blackish.

- Transparency : translucent to opaque
- Hardness : 10
- S.G. : not higher than 3.505
Boart is less and less used in the industry and to a great extend replaced by synthetic diamonds.
Occurrence :
The great majority of Boart comes from the  Democratic Republic of Congo and Brazil. The stones from the latter country being more valuated because they have less fissures and therefore are more resistant.

BOBROWKA GARNET :
Synonym for Grossular, for others synamey for Demantoid. (Source : Robert M. Shipley)

BOCCO DE DOGO :
Brazilian Name given to a green Tourmaline with a red centre.

BOCCO DE FOGO :
Brazilian. Crystal of Tourmaline  : green with a pink centre. (Source : Robert M. Shipley)

BODENBENDERITE :
German. Mixture of Spessartite and Fluorite.

BODENSTEIN :
German. Synonym for Amber. (Source : index mineralogical British Museum)

BOHEMIAN CRYSOLITE :
Prohibited appellation : moldavite. (Source : Robert M. Shipley)

BOHEMIAN DIAMOND :
Prohibited appellation : rock crystal. (Source : Robert M. Shipley)

BOHEMIAN GARNET :
Prohibited appellation designating an intense dark red pyrope. (Source : Robert M. Shipley)

BOHEMIAN RUBY :
Prohibited appellation : for a Quartz, pink or red or for a pyrope garnet .. (Source : Robert M. Shipley).

BOHEMIAN TOPAZ :

Prohibited Appellation for a yellow quartz or citrine or for a yellow fluorite . (Source : Robert M. Shipley)

BURNT TOPAZ :

Yellow topaz that has been heated at low temperatures to give it a pink colour.

BOIS SILICIFIE :
French for silicified wood.

BOLIVARITE :
Variety of Variscite from Spain.

BOLIVIAN JASPER :
Red Jasper from Bolivia. (Source : Robert M. Shipley)

BOLOPHENITE :
Synonym for Hedenbergite.

BOMBITE :
Variety of Melanite.

BONAMITE :
ZnCO3.
Carbonate of zinc (See Smithsonite, the only name authorised for this carbonate).

BONE AMBER :
Variety of Amber more opaque than the traditional amber and resembling bone or ivory. (Source : Robert M. Shipley)

BONY AMBER :
See bone amber. (Source : Robert M. Shipley)

BONE TURQUOISE :
Prohibited appellation : fossilized bone or tooth with natural nice blue colour (colour due to vivianite). (Source : Robert M. Shipley)

BORACITE :
Collector’s stone.

Mg₃[Cl|B₇O₁₃]
Physical and optical properties :
- Colour : pale green

- Transparency : transparent

- Lustre : vitreous to adamantine.
- Hardness : 7
- S.G. : 2.96
- R.I. : 1.661 to 1.671
- Crystal system : cubic.
- Slightly greenish under U.V.
Occurrence :
Germany, U.S.A.

BORAZON :
Trade-name; CBN = cubic boron nitride; a synthetic material produced for abrasive purposes since 1957.

BN

Hardness : equals diamond ; borazon scratches diamond and vice-versa.

BN :
Boron nitride. Synthetic abrasive much used in industry because more resistant to high  temperatures and of equal or superior hardness than industrial or natural diamond.

BN
Physical and optical properties :
- Colour : black, brown, dark red, milky white, grey, yellow.
- S.G. : 3.45

BORNITE :
Collector’s stone

Sulphide of copper with metallic blue to violet lustre.
Cu₅FeS₄
Physical and optical properties :
- Colour : copper red.
- Hardness : 3
- S.G. : 4.9 to 5.4
- R.I. :
- Crystal system : cubic

BÖRNSTEIN :
German. Synonym for Amber. (Source : mineralogical index British Museum)

BORT :
Synonym  for Boart.

BORTZ :
Synonym for Boart. (Source : Robert M. Shipley)

BOSTRICHITES :
Synonym for Prehnite. (Source : mineralogical index British Museum)

BOTTLE STONE :
Prohibited appellation for chrysolite.
For others : for Moldavite. (Source : Robert M. Shipley)

BOULDER OPAL :
Term used by miners for nodules enclosing precious opal in Queensland (Australia). (Source : Robert M. Shipley)

BOURGUIGNON PEARL :
Prohibited appellation for imitation pearls filled with wax. (Source : Robert M. Shipley)

BOWENITE :
Name of the most common variety of Serpentine, member of the sub-group of the antigorites (comprising also Wiliamsite).
Etym. : name comes from G.T. Bowen who found the first ones on Rhode Island in 1922.
3(Mg, Fe)O.2SiO₂.2H₂O  
Physical and optical properties :
- Colour : oily green, white, colourless with small whitish spots of chlorite, blue-greenish, apple green.
- Hardness : 5 to 6
- S.G. : average : 2.57 to 2.59
- R.I. : 1.56

- Crystal system : monoclinic
- Absorption lines at 497 nm and 464 nm.
- Fluorescence : greenish-white for the palest stones.
Occurrence :
South Island (New Zeeland) ; Pakistan ; Afghanistan ; China ; Kashmir.
Prohibited Appellations :
- Nouveau Jade : French. Prohibited appellation designating Bowenite.
- New Jade : Prohibited appellation designating la Bowenite.
- Soochow Jade : Prohibited appellation designating Bowenite.
- Korean Jade : Prohibited appellation designating Bowenite.

(BOWENITE) JADE :
Prohibited Appellation for a Bowenite.

BOWR :
Synonym for Boart. (Source : Robert M. Shipley)

BRAGANZA TOPAZ :
Sometimes wrongly called Braganza Diamond; is a colourless Topaz of 1680 carats of unusual beauty belonging to the Portuguese crown.

BRAUNSTEINKIESEL :
German. Synonym for Spessartine.

BRAZILIAN AMETHYST :
Amethyst from Brazil. Principally from the Brejinha mine, Bahia and from Rio Grande Do Sul, Brazil. (Source : Robert M. Shipley)

BRAZILIAN AQUAMARINE :
Prohibited appellation : for a greenish topaz .
= Aquamarine from Brazil. (Source : Robert M. Shipley)

BRAZILIAN CHRYSOLITE :
Prohibited appellation  = same as chrysolite-chrysoberyl. (Source : Robert M. Shipley)

BRAZILIAN DIAMOND :
Prohibited appellation for rock crystal from Brazil. (Source : Robert M. Shipley)

BRAZILIAN EMERALD :
Prohibited appellation for green tourmaline.
Means also emerald from Brazil. (Source : Robert M. Shipley)

BRAZILIAN ONYX :
Prohibited appellation for an onyx-marble of superior quality and colour coming actually from Argentina. (Source : Robert M. Shipley)

BRAZILIAN PEBBLE :
Prohibited appellation for rock crystal. (Source : Robert M. Shipley)

BRAZILIAN PERIDOT :
Prohibited appellation for pale yellow-green tourmaline. (Source : Robert M. Shipley)

BRAZILIAN RUBY :
Prohibited appellation for red-pink or pink Topaz whether natural or artificially coloured. (Source : Robert M. Shipley)

BRAZILIAN SAPPHIRE :
Prohibited appellation for pale blue or greenish topaz or also for blue tourmaline. (Source : Robert M. Shipley)

BRAZILIAN TOPAZ :
= natural yellow Topaz. (Source : Robert M. Shipley)

BRAZILIANITE :
Or Brasilianite.

Collector’s stone.

Etym. : name after Brazil, where it was discovered early 1940’s ; still it’s main source (near Conseilheiro Pena, Divino District, Minas Gerais)
Basic phosphate of sodium and aluminium.
NaAl₃[PO₄]₂(OH)₄
Physical and optical properties :
- Colour : yellow, yellow-green

- Transparency : transparent to translucent

- Lustre : vitreous
- Hardness : 5.5
- S.G. : 2.980 to 2.995
- R.I. : 1.598 - 1.621 (± 0.004) (Birefr. : + 0.019 to 0.021)
- Biaxial positive.
- Crystal system : monoclinic (short prisms).
- Cleavage : sometimes, and easy in the direction parallel to one pinacoidal face.
- Fracture : conchoidal.
- Very weakly dichroic.
- Fluorescence none.
- Bluish under Chelsea filter
Occurrence :
The only important sources are located in Brazil.
Inclusions :
A lot of two-phase inclusions.
Confusions :
- Amblygonite (S.G.: 3.01 to 3.11 ; R.I.: 1.61 to 1.63 ; Birefringence slightly superior : 0.026)
- Chrysoberyl (S.G. : 3.71 ; R.I. : 1.75).
- Peridot (S.G. : 3.34 ; R.I. : 1.65 to 1.68 ; strong birefringence).
- Diopside chromiferous (S.G. : 3.39 ; R.I. : 1.67 to 1.70 ; strong birefringence).
See also:
Aus der gemmologischen Prüfungspraxis, by H. Bank, (ZDG 18, n°4 ,  1969, page 190).

BREDBERGITE :
Variety of Andradite garnet.

BREITHAUPTITE :
Collector’s stone.

Arsenide of nickel and antimony.
NiSb
Physical and optical properties :
- Colour : copper-red to violet with sometimes violet spots

- Transparency : opaque

- Lustre : metallic
- Hardness : 4.5 to 5.5
- S.G. : 8.23
- Crystal system hexagonal.

Occurrence :

St Andreasberg, Harz Mountains, Lower Saxony , Germany

BRIANCON DIAMOND :
Prohibited appellation for Quartz. (Source : Robert M. Shipley)

BRIGHTON DIAMOND :
Prohibited appellation : for a rock crystal. (Source : Robert M. Shipley)

BRIGHTON EMERALD :
Prohibited appellation :for a bottle-green glass. (Source : Robert M. Shipley)

BRILLIANT :
The word brilliant used on its own should only be applied to a diamond cut with crown and pavilion-side together having habitually 57 facets.

BRISTOL DIAMOND :
Prohibited appellation for rock crystal. (Source : Robert M. Shipley)

BRITISH AMBER :
Prohibited appellation for amber from the Baltic Sea having been washed ashore on the beaches of Great-Britain. (Source : Robert M. Shipley)

BRITTLE AMBER :
Prohibited appellation for geddanite. (Source : Robert M. Shipley)

BRODDBOGRANAT :
German. Synonym for Spessartite. (Source : mineralogical index British Museum)

BROMELLITE :
Oxide of Beryllium;

artificial Bromellite produced by the flux-fusion method.
BeO
Physical and optical properties :
- Colour : Colourless to white
- Hardness : 9
- S.G. : 3.00 to 3.10
- R.I. : 1.720 - 1.735 (Birefr. : 0.015).
- Uniaxial positive.
- Crystal system hexagonal.
- Fluorescence : orange under L.W.U.V.
See also:
Modern Synthetic Gemstones, by R. Webster (TJG vol.12 n°4 , 1970, page 115).

BRONCITA :
Spanish for Bronzite.

BRONZE PEARL :
Variety of black pearl with a bronze coloured tint. (Source : Robert M. Shipley)

BRONZITE :
Variety of enstatite / hypersthene with a lustre like bronze.
(Mg,Fe)₂[Si₂O₆].
Physical and optical properties :
- Colour : bronze, yellowish-brown to brown-green; for Bronzite cat’s eye :  dark brown with a clear metallic-shining yellow line.

- Transparency : transparent to opaque

- Lustre : vitreous to mettallic
- Hardness : 5 to 6
- S.G. : 3.25
- R.I. : 1.663 – 1.677 (Birefr. : 0.014)

- Biaxial positive

- Crystal system : orthorhombic
Occurrence :
Austria.

BRONZITE CAT’S EYE:
= bronzite with chatoyant effect.

BROOKITE :
One of the three forms of titanium dioxide (Brookite, Anatase, Rutile).
TiO₂
Only rarely cut. For collectors.
Physical and optical properties :
- Colour : yellowish, light brown or red-brown.

- Transparency : transparent to translucent

- Lustre : adamantine metallic.
- Hardness : 5.5 to 6
- S.G. : 3.87 to 4.10
- R.I. : 2.583 - 2.705 (up to 2.741) (Birefr. : 0.122 to 0.158)
- Biaxial positive.
- Crystal system : orthorhombic.
- Cleavage : following the pyramid and the prism.
Occurrence :
France, Switzerland, U.S.A., Russia.
Inclusions :
Fine parallel channels.

BROWN HEMATITE :
Prohibited appellation for limonite. (Source : Robert M. Shipley)

BROWN HYACINTH :
Prohibited appellation for vesuvianite. (Source : Robert M. Shipley)

BRUCIATO :
Italian name for dark brown to blackish coral, discoloured by having been on the bottom of the sea for a long time. (Source : Robert M. Shipley)

BRUIACHITE :
Synonym for Fluorite.

BUCKHORN PEARL :
Fresh water pearl of spherical form from the mussels of the Mississippi. (Source : Robert M. Shipley)

BUCKLANDITE :
Variety of black Epidote according to Hermann, or synonym for allanite of Levy.

BUFFLE`S EYE :

Variety of tiger’s eye with a red-brown colour

BULB OPAL :
Menelite opal. (Source : Robert M. Shipley)

BULL`S EYE :

Name used for labradorite with strong red iridescence

BULLHEAD PEARL :
Fresh water pearl from the mussels of North America. (Source : Robert M. Shipley)

BURMA JADE :
Synonym for Burmese jade. (Source : Robert M. Shipley)

BURMA MOONSTONE :
Moonstone from Burma. (Source : Robert M. Shipley)

BURMA SAPPHIRE :
Term used in America for a sapphire, royal blue in colour, coming from Burma or not.

BURMESE JADE :
Synonym for Burmese jadeite.

BURMESE JADEITE :
Synonym : Burmese jade.
Synonym soda-jadeite. (Source : Robert M. Shipley)

Finest known jadeite. From mines in Mogaung, subdivision of Myitkyina district in Upper Burma.

Burma jade is the term used in the Orient to distinguish it from varieties of Nephrite.

BURMESE SPINEL :
Red spinel found in the form of a perfect octahedron and of gem-quality near Mogok. (Source : Robert M. Shipley)

BURMITE :
Ancient term designating amber coming from Burma.

BURNT AMETHYST :
American Appellation for an Amethyst that turned yellow after heating.

BURNT CAINGORM :
American Appellation for a Quartz heated and turned into the colour of topaz.

BURNT TOPAZ :
Topaz of which the colour has been changed by heat-treatment into pink. (Source : Robert M. Shipley)

BUSTAMITE :
Silicate related to Rhodonite.

BUTTERFLY PEARL :
Pearl from the Mississippi Valley. One of the most beautiful sweet water pearl varieties in existence. (Source : Robert M. Shipley)

BUTTON ONYX :
Opal or agate with alternating bands of black chalcedony and common opal. (Source : Robert M. Shipley)

BUTTON OPAL :
Synonym button onyx. (Source : Robert M. Shipley)

BUTTON PEARL :
Pearl of which the surface is almost flat. (Source : Robert M. Shipley)

BUXTON DIAMOND :
Prohibited appellation for rock crystal.

BYSSOLITE :
A kind of brown asbestos.
The colour and fibres of byssolite evocate the Byssus of pearl oysters thanks to which they can attach themselves to a surface.