Rock Crystal Gemstone & Information | Gemopedia by JTV | Gemopedia™

Rock Crystal

Rock crystal is colorless quartz. Due to its clarity, rock crystal is the perfect canvas for a myriad of attractive mineral inclusions, including purple fluorite crystals, golden needles of rutile, metallic pyrite cubes, and many others.

Colors

Colorless

  • Rock-crystal classification

    CommonName
    Rock Crystal
    Species
    Quartz
    Variety
    Rock Crystal
    Colors
    Colorless
    AlternateNames
    GemstoneGroups
    KeySeparations
    Refractive index, birefringence, optic character and optic figure. A bull's-eye optic figure is determinative for quartz; may also show Airy's spiral optic figure and Brazil-law twinning under crossed polarizing filters.
    ClassificationComments
    Colorless quartz with visible needle-like inclusions is a variety called "sagenitic." Stones with red hematite inclusions or "beetles-legs" may take a reddish appearance and be called "strawberry quartz." If colorless quartz contains golden blades of rutile it is often called "rutilated quartz."Misnomers: Herkimer diamond, Arizona diamond, Arkansas diamond, Alaska diamond, Cornish diamond. Rhinestones get their name from the rock crystal from the Rhine river that was cut and polished and used as diamond imitations.
  • Rock-crystal chemistry & crystallography

    ChemicalName
    silicon dioxide (aka silica)
    ChemicalFormula
    SiO2
    Synthesis
    CrystalSystem
    Trigonal
    ChemistryClassification
    Silicate
    Nature
    Natural
    Crystallinity
    Crystalline
    ChemistryComments
  • Rock-crystal optical properties

    Transparency
    Transparent
    Dispersion
    Strength: weak fire Value: 0.013
    OpticalComments
    RefractiveIndex
    1.544-1.553
    Tolerance:very constant
    Birefringence
    0.009
    OpticCharacter
    Uniaxial
    OpticSign
    Positive
    PolariscopeReaction
    Doubly Refractive (DR)
    Fluorescence
    SWUV: Inert
    LWUV: Inert
    CCFReaction
    none
    Pleochroism
    None
  • Rock-crystal characteristic physical properties

    Hardness
    7
    CharacteristicComments
    Streak
    White
    SpecificGravity
    2.64-2.69 Range:0.03/-0.02 Typical:2.66
    Toughness
    Good
    Inclusions
    Rock crystal is a type II clarity stone and might contain liquid, two-phase and three-phase inclusions, negative crystals, minerals, needles, rutile and iron particles
    Luster
    Vitreous
    Stability
    Good
    Fracture
    Conchoidal
    Cleavage
    None