RACINE D'AMETHYSTE :

French Prohibited Appellation for a violet fluorite .

RACINE D'EMERAUDE :

French Prohibited Appellation for a green fluorite

RACINE de JADE :

French Prohibited Appellation for a green fluorite  .

RADAUITE :

Variety of labradorite .

RADIOTINE :

Serpentine in spherical aggregates composed of radiant fibres, found near Dillenburg (Wiserwald) Nassau-Germany .

RANDANITE :

Variety of opal .

RANSATILE :

Name given to an impure manganiferous garnet .

RAPHILITE :

Synonym for tremolite .

RAPIDOLITE :

Synonym for wernerite .

RASPBERRY SPAR :

English Name for a rhodocrosite, equally incorrect term for a pink tourmaline .

RATOFKITE :

Variety of impure fluorite .

RAUCHQUARTZ :

German Name for a smoky quartz .

RAUCHTOPAZ :

German Prohibited Appellation for a smoky quartz .   

RAUMITE :

Variety of prasiolite  .

REDMANOL :

Variety of plastic product based on a melted phenol resin, with a composition close to bakelite .

RED SCHORL :

Prohibited Appellation for a rutile .

REESE TURQUOISE :

Prohibited Appellation for an imitation of turquoise of Reese fabrication .

REGALITE :

Variety of opaque greenish Quartz .

RESINITE :

Variety of common opal with a resinous aspect .

RESINOIDE :

Synonym for the plastic bakelite

RETINALITE :

Variety of serpentine , massive yellow to light greenish possessing a waxy lustre : it belongs to the  group of Bowenite and Williamsite.

RETINITE :

Fossil resin, or variety of obsidian of a more or less dark brown chocolate colour.

RHABDOLITHE :

Synonym for wernerite .

RHADEZITE :

Synonym for cyanite .

RHAETIZITE :

Variety of disthene in fibrous masses, sometimes whitish, sometimes coloured black by graphite .

RHENITE :

Synonym for pseudomalachite .

RHODICITE :

Synonym for rhodizite .

RHODIZITE :

(Cs,K,Rb)Al₄Be₄[B₁₁O₂₆(OH)₂]

Physical and optical properties :

Colour : colourless, grey pale, yellow pale, white greenish, red

Transparency : transparent to translucent

Lustre : silky

Hardness : 8

Density : 3.40

R.I. : 1.690

System : cubic

RHODOCHROSITE :

Synonym : dialogite

Etym. : from the Greek rhodochros = pink colour

MnCO₃     

Physical and optical properties :

Colour : pink (skin colour), vivid pink, light pink veined with white, having sometimes inclusions of pyrite .

Transparency : transparent to opaque

Hardness : 3.5 to 4.5

Density : 3.31 to 3.74

R.I. : 1.580 (+0.020 –0.002) – 1.790 (+0.030 –0.004)

              Up to 1.600 (-0.022) – 1.820 (-0.034)

Birefringence : 0.208 to 0.220

Dispersion : 0.010 to 0.020

Uniaxial negative

System : trigonal

RHODOLITE :

Etym. From the Greek: rhodon = pink  and lithos = stone

Variety of garnet intermediate between almandine garnet and  pyrope garnet, is equally called pyrandine and is often associated with corundum .

Physical and optical properties :

Colour : pink to pink violet, purple-red

Transparency : transparent

Hardness : 7 to 7.5

Density : 3.74 to 4.20

R.I. : 1.74 to 1.81

System : cubic

RHODONITE :

Etym. From the Greek rhodon = pink

CaMn₄[Si₅0₁₅]       

Physical and optical properties :

Colour : pink (skin colour), vivid to washed pink with fine black veins for pyrolusite, brownish pink

Transparency : transparent to opaque

Hardness : 5.5 to 6.5

Density : 3.40 to 3.74

R.I. : 1.733 (+0.05 –0.017) – 1.744 (+0.008 –0.021)

Birefringence : 0.010 to 0.014

Biaxial positive or negative

Dichroism distinct : red yellowish, red-pink

System : triclinic

RHYACOLITE :

Synonym for sanidine   

RHYOLITE GLASS :

Forbidden Appellation for an obsidian .

RIACOLITE :

Synonym for sanidine  .

RICOLITE :

Mixture of serpentine and talc, or only serpentine with fine grains and coloured bands of dark green mixed with yellow and yellowish green; there can also occur tones of reds, blues and browns .

RIPONITE :

Synonym for mirzonite .

ROCK CRYSTAL :
Synonyms : hyalin quartz, transparent colourless quartz.
Silicon dioxide of.

SiO2.
Physical and optical properties:
- Colours : Colourless

ROCK CRYSTAL :

Synonyms : hyalin quartz, transparent colourless quartz.
Silicon dioxide of.

SiO2.
Physical and optical properties:
- Colours : Colourless
- transparency : transparent
- lustre : vitreous
- Hardness : 7
- S.G. : 2.65
- R.I. : 1.544 - 1.553 (Birefr : +0.009)
- Uniaxial positive
- Pleochroism none.
- After a more or less long exposure to X-rays, rock crystal becomes smoky or light yellow in colour.
- Cleavage none.
- Fracture conchoidal.
- Crystal system : trigonal
Occurrences :
Largely found throughout the world in different environments: pegmatites, granitic or extrusive rocks, in geodes, … .
French and Swiss Alps, Brazil, Madagascar, Japan, Australia, … .
Treatments :
Rock crystal can take on the colour of smoky quartz or become light yellow under the effect of radium and of X -rays.
Inclusions :
Often rich in inclusions of tourmaline (needles).
Inclusions of" negative crystals " with or without two-phase filling, polyedrical cavities with faces parallel to the faces of the rough crystal. Strong relief.
Decrepitated inclusions of crystals of rock crystal itself in the interior of the crystal.
Synthetics :
Hydrothermal synthesis of quartz exists and is widely used in industry as well as in jewellery.
Confusions :
- Orthose colourless (S.G. : 2.56 ; R.I. : 1.52 to 1.53)
- Beryl colourless (S.G. : 2.7 ; R.I. : 1.56 to 1,60)
- Topaz (S.G. : 3.4 to 3.6 ; R.I. : 1.60 to 1.63)
- Tourmaline acroite (S.G. : 2.9 to 3.2 ;R.I. : 1.61 to 1.65 ; rare).
- Sapphire white (S.G. : 4 ; R.I. : 1.759 to 1.769 ; very rare).
- Zircon (S.G. : 4 to 4.7 ; R.I. : 1.92 to 1.96 ; fort doubling of facet junctions).
- Glass ( S.G. & R.I. variable ; gas bubbles ; traces of fusion)

ROCKLANDITE :

Variety for serpentine  .

ROCK RUBY :

Prohibited Appellation for a pyrope garnet .

ROEPPERITE :

Variety for peridot containing Zn, used also as synonym for rhodocrosite containing Ca .

ROGUEITE :

Local Name for a green jasper from Rogue Rivers, Oregon .

ROMONITE :

Synonym for rumanite .

ROMANZOWITE :

Variety of dark brown transparent grossular garnet ; Etym. : dedicated to the Russian geologist Romasoff, and found in Finland .

ROOTHOFFITE :

Etym. Dedicated to the Swiss mineralogist Roothoff .

Variety of melanite garnet of brown-yellow to brown-grey colour .

ROSALINE :

Synonym for thulite .

ROSE GARNET :

(English) Synonym for rhodolite, or commercial name for an ornamental stone containing rosolite, vesuvianite, and coming from Xalostoc in Mexico .

ROSEKI :

Japanese Term for an agalmatolite .

ROSE KUNZITE :

Prohibited Appellation, English commercial term, designating a sapphire or a synthetic spinel of pink colour .

ROSE MOONSTONE :

Prohibited Appellation for a pink scapolite .

ROSENSPATH :

Synonym (German) for rhodocrosite  

ROSE QUARTZ :

Variety of Quartz mostly massive and a little turbid, rarely well formed crystals with flat faces (and then small). The presence of oriented rutile needles causes a six-rayed star. Colour : pink.

ROSINCA :

Commercial Name in Argentina for a banded rhodocrosite .

ROSOLITE :

Synonym for landerite .

ROSOPAL :

Synonym for quincyte or a variety of opal with a pink base .

ROSST EVORITE :

Variety fibrous epidote .

ROSTERITE :

Variety of pink-red Beryl .

ROTHBRAUNSTEINERZ :

German Synonym for rhodonite .

ROTHEISENERZ :

German Synonym for hematite .

ROTHOFFITE :

Synonym for Roothoffite  .

ROTHSTEIN :

A German Name for Rhodonite .

ROUMANITE :

Variety of amber from Rumania .

ROYAL ISLE GREENSTONE :
English Name for a Chlorastolite.

ROYALITE :

Commercial Name for a red-purple glass .

ROYITE :

Synonym for Quartz  .

ROZIRCON :

Prohibited Appellation designating a synthetic pink spinel .

RUBASSE :

Variety of rock crystal coloured by red inclusions of iron. The natural stone found in Brazil is very rare and is imitated by crackled rock crystal and coloured artificially red .

RUBELLITE :

Red to pink-red tourmaline .

RUBICELLE :

Prohibited Appellation for an orange or yellow spinel .

RUBIN :

German Name for ruby .

RUBEIZEN :

German Name for goethite  .

RUBINO-DI-ROCCA :

Prohibited Appellation, Italian name for a red garnet with a violet tinge .

RUBINSPATH :

Prohibited Appellation, German name for rhodonite .

RUBIS :

French for ruby.

RUBIS ALABANDINE :

Ancient French term,  originally designating an almandine garnet coming from Alabanda in Asia Minor.

Equally a Prohibited Appellation for a red-violet spinel, equally called Alabanda Ruby .

RUBIS ADELAIDE :

Prohibited Appellation , French, for a blood red pyrope from South Africa .

RUBIS ASTERIE :

(French) Synonym for the French term ‘rubis étoilé’ ( star ruby ).

RUBIS BALAIS or BALAIS :

French for balas ruby.

RUBIS DU MONT BLANC :

French term . Prohibited Appellation for a pink Quartz .

RUBIS ETOILE :

French for star ruby .

RUBIS SANG de BOEUF :

French term. Designates a ruby with a colour more dark red than pigeon blood red colour .

RUBOLITE :

Variety of common opal with red colour .

RUBY :

Etym. from Latin : Rubeus = red

A1₂0₃

Variety of corundum with colours : red, ‘pigeon’ blood red and light pinkish-red to dark brown-red

(ALMANDINE) RUBY :

Prohibited Appellation for a spinel, or for a red garnet .

(AMERICAN) RUBY :

Prohibited Appellation for a red garnet .

(ANCONA) RUBY :

Prohibited Appellation for a reddish or brownish Quartz coloured by iron oxides .

(ARIZONA) RUBY :

Prohibited Appellation for a dark red pyrope from Arizona or from Utah .

(AUSTRALIAN) RUBY :

Prohibited Appellation for a red garnet .

(BALAS) RUBY :

Prohibited Appellation for a red-pink spinel .

(BOHEMIAN) RUBY :

Prohibited Appellation for a pink or red Quartz or for a pyrope garnet .

(BRAZILIAN) RUBY :

Prohibited Appellation for a red-pink or pink topaz whether natural or artificially coloured .

(CALIFORNIAN) RUBY :

Prohibited Appellation for a garnet .

(CAPE) RUBY :

Prohibited Appellation for a pyrope garnet .

(CEYLAN) RUBY:

Old name for ruby from Sri Lanka .

Equally a prohibited appellation for an almandine garnet .

(COLORADO) RUBY :

Prohibited Appellation for a pyrope garnet .

(FASHODA) RUBY :

Prohibited Appellation for a dark red to brownish red pyrope garnet from Tanganyika (source :! Robert M. Shipley) .

(MEXICAN) RUBY :

Prohibited Appellation for a for fire opal of red colour .

(MONTANA) RUBY :

Prohibited Appellation for a red garnet .

(OCCIDENTAL) RUBY :

Very old term sometimes used for a true ruby to differentiate it from spinel .

(PIGEON BLOOD) RUBY :

Designates the most desired nuance of red colour for a ruby (= a very fine dark,  very luminous red ) .

(SIBERIAN) RUBY :

Prohibited Appellation for a red tourmaline .

(SPINEL) RUBY :

Prohibited Appellation for a red spinel . 

(SYNTHETIC) RUBY :

Artificial ruby made by man having the same structure and the same chemical composition .

RUMANITE :

Variety of amber ; brownish yellow to red, rarely yellow, sometimes black .

RUTILE :

Etym.: du latin: rutilus = reddish

Found as inclusions (often as needles) in Quartz (sagenitic Quartz, Venus hair), in ruby, in sapphire, in almandine garnet, etc.

TiO₂      

Physical and optical properties :

Colour : red sang, brown reddish, yellowish, golden yellow-blond, black

Transparency : transparent to opaque

Hardness : 6 to 6.5

Density : 4.2 to 4.3

R.I. : 2.616 – 2.903

Birefringence : 0.287

Dispersion : 0.150 (±0.030)

Biaxial positive

System : tetragonal

(SYNTHETIC)  RUTILE:

See titania .

RUTILE QUARTZ :

Variety of rock crystal with rutile needles (of yellow to golden colour; called also Venus hair) as inclusions .