Rock Crystal

Big Photo

Crystalline Quartz Dreamscape Cut
16.93 carats
© johndyergems.com

Rock Crystal is a traditional name given to water-clear crystalline quartz.

The name Crystal comes from the Greek for "ice", as it was believed that Rock Crystal was eternally frozen. Rock Crystals weighing many tons have been found. Cuttable material is rare.

Rock Crystal is used for costume jewelry and delicate bowls and to imitate diamonds.

Rock Crystal Gemstones by Colour

This table shows the variety of hues this gemstone can be found in. Click on a photo for more information.
 

Rock Crystal Gemstones by Size

This table shows distribution of Rock Crystal gemstone sizes that are listed on this site. This can give a good indication as to the general availability of this gemstone in different sizes.
Contributed photos
Lightest:7.62 cts
Heaviest:72.07 cts
Average:29.82 cts
Total photos:11
Do you have a larger Rock Crystal? Why not upload a photo?
7.62ct to 14.07ct14.07ct to 20.51ct20.51ct to 26.96ct26.96ct to 33.40ct33.40ct to 39.85ct39.85ct to 46.29ct46.29ct to 52.74ct52.74ct to 59.18ct59.18ct to 65.63ct65.63ct to 72.07ct
General Information
A variety or type of:Quartz
Chemical Formula
SiO
 
2
Walter Schumann, Gemstones of the world (2001)
Photos of natural/un-cut material from mindat.org
Rock Crystal Treatments
Cracks are induced (heating and quick cooling) then dyed in any color, magnification: web-like network. Iris, rainbow quartz have iridescence due to cracks. Coated (all colors) with ultra-thin layer of metallic elements (gold for light blue "Aquaaura"), color concentration along facet junctions or irregular distribution, peeled coating. Sharp blade, acetone, acid tests - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 7
Rock Crystal Simulants
Imitations made of quartz triplets are common - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 7
Synthetic Rock Crystal
Synthetic rock crystal is used only for industrial purposes. - Gemstones of the world, Walter Schumann, 2001, p 116
Physical Properties of Rock Crystal
Mohs Hardness7
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Specific Gravity2.65
Walter Schumann, Gemstones of the world (2001)
More from other references
TenacityBrittle
Walter Schumann, Gemstones of the world (2001) Very brittle
Cleavage QualityNone
Walter Schumann, Gemstones of the world (2001)
FractureConchoidal
Walter Schumann, Gemstones of the world (2001)
Optical Properties of Rock Crystal
Refractive Index1.544 to 1.553
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Optical CharacterUniaxial/+
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Birefringence0.009
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
PleochroismAbsent
Walter Schumann, Gemstones of the world (2001)
Dispersion0.013
Walter Schumann, Gemstones of the world (2001)
ChatoyancyStar 4/6/12 (rare)
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Colour
Colour (General)Colorless
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
More from other references
TransparencyTransparent
Walter Schumann, Gemstones of the world (2001)
More from other references
LustreVitreous
Walter Schumann, Gemstones of the world (2001)
Fluorescence & other light emissions
Fluorescence (General)None
Walter Schumann, Gemstones of the world (2001)
Crystallography of Rock Crystal
Crystal SystemTrigonal
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
HabitHexagonal prisms
Walter Schumann, Gemstones of the world (2001)
Geological Environment
Where found:Rock crystal is found widespread in the world.
Michael O’Donoghue, Gems, Sixth Edition (2006)
Inclusions in Rock Crystal
Huge variety of inclusions such as 2 phase inclusions, golden rutile needles ("Venus hair"), black tourmaline crystals, fibers of green actinolite, mossy-like green chlorite, dark red hematite - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 7
Further Information
Mineral information:Rock Crystal information at mindat.org
Significant Gem Localities
Myanmar
 
  • Mandalay Region (Mandalay Division)
    • Pyin-Oo-Lwin District
      • Mogok Township
        • Kyauk-Pyat-That
Kammerling et al. (1994)
Peru
 
  • Huancavelica Department
    • Castrovirreyna Province
  • La Libertad Department
    • Sanchez Carrion Province
      • Huamachuco
        • Mundo Nuevo
  • Pasco department
    • Pasco province
      • Huayllay district
        • Huaron mining district
Sri Lanka
 
  • Sabaragamuwa Province
    • Ratnapura District
      • Ratnapura
Copyright © Jolyon & Katya Ralph 1993-2017. Site Map. Locality, gem & photograph data are the copyright of the individuals who submitted them. For more information please contact the . Gemdat.org is an online information resource dedicated to providing free gemmological information to all.