Abstract
The fibrillar growth habit and {100} twinning of fibrous amphiboles tend to produce anomalous optical properties. Commercial amosite and crocidolite always exhibit uniaxial-like optical properties including parallel extinction and two principal indices of refraction. Fibrous members of the actinolite series, however, exhibit a range in optical properties from normal to anomalous. The types of anomalous optical properties that can be displayed by asbestiform members of the actinolite series are described based on a study of twelve samples. One sample displays uniaxial-like properties, nine display partial development of uniaxial-like properties, and two contain fibers with both orthorhombic and monoclinic optical properties. “Byssolitic” samples of the actinolite series, a fibrous non-asbestiform habit, contain fibers that do not go to extinction in sections on or near (010), probably as a result of {100} twinning. Although anomalous optical properties may confound the identification of fibrous amphiboles, in most cases the refractive indices are predictable and can be used for identification. Because of the range in optical properties, especially extinction angle, reliance solely on parallel extinction to distinguish asbestos from non-asbestiform varieties is not recommended. The fibrillar structure, however, remains the hallmark of the asbestiform habit.
© 2015 by Walter de Gruyter Berlin/Boston
Articles in the same Issue
- Evidence for magmatic vapor deposition of anhydrite prior to the 1991 climactic eruption of Mount Pinatubo, Philippines
- Experimental and modeled solubilities of chlorine in aluminosilicate melts, consequences of magma evolution, and implications for exsolution of hydrous chloride melt at Mt. Somma-Vesuvius
- Temperature-induced Al -zoning in hornblendes of the Fish Canyon magma, Colorado
- Analytical techniques for volatiles: A case study using intermediate (andesitic) glasses
- Anomalous optical properties of fibrous tremolite, actinolite, and ferro-actinolite
- Protoanthophyllite from three metamorphosed serpentinites
- Synthesis of beryllian sapphirine in the system MgO-BeO-Al2O3-SiO2-H2O and comparison with naturally occurring beryllian sapphirine and khmaralite. Part 1: Experiments, TEM, and XRD
- Intersite distribution of Fe2+ and Mg in the spinel (sensu stricto)–hercynite series by singlecrystal X-ray diffraction
- Structural relationships in (Mn1–xZnx)Mn2O4 (0 ≤ x ≤ 0.26): The “dragging effect” of the tetrahedron on the octahedron
- The grid-work texture of authigenic microcrystalline quartz in siliceous crust-type (SCT) mineralized horizons
- The crystal structure of vicanite-(Ce), a borosilicate showing an unusual (Si3B3O18)15– polyanion
- Submicrometer optical characterization of the grain boundary of optically active Cr3+ doped polycrystalline Al2O3 by near-field spectroscopy
- High-temperature, high-pressure optical spectroscopic study of ferric-iron-bearing tourmaline
- Infrared and Mössbauer study of Brazilian tourmalines from different geological environments
- Isothermal compression of staurolite: A single-crystal study
- Equation of state measurements of chlorite, pyrophyllite, and talc
- Structure change of Ca1–xSrxTiO3 perovskite with composition and pressure
- Mechanism of 2/1- to 3/2-mullite transformation at 1650 °C
- High-pressure deformation mechanism in scolecite: A combined computationalexperimental study
- Far infrared spectra of K+ in dioctahedral and trioctahedral mixed-layer minerals
- Ab initio quantum mechanical modeling of infrared vibrational frequencies of the OH group in dioctahedral phyllosilicates. Part I: Methods, results and comparison to experimental data
- Ab initio quantum mechanical modeling of infrared vibrational frequencies of the OH group in dioctahedral phyllosilicates. Part II: Main physical factors governing the OH vibrations
- On geological interpretations of crystal size distributions: Constant vs. proportionate growth
- Allabogdanite, (Fe,Ni)2P, a new mineral from the Onello meteorite: The occurrence and crystal structure
- Cristobalite inclusions in the Tatahouine achondrite: Implications for shock conditions
- Letters. Natural occurrence of Fe2SiO4 -spinel in the shocked Umbarger L6 chondrite
- Structural refinements of magnesite at very high pressure
Articles in the same Issue
- Evidence for magmatic vapor deposition of anhydrite prior to the 1991 climactic eruption of Mount Pinatubo, Philippines
- Experimental and modeled solubilities of chlorine in aluminosilicate melts, consequences of magma evolution, and implications for exsolution of hydrous chloride melt at Mt. Somma-Vesuvius
- Temperature-induced Al -zoning in hornblendes of the Fish Canyon magma, Colorado
- Analytical techniques for volatiles: A case study using intermediate (andesitic) glasses
- Anomalous optical properties of fibrous tremolite, actinolite, and ferro-actinolite
- Protoanthophyllite from three metamorphosed serpentinites
- Synthesis of beryllian sapphirine in the system MgO-BeO-Al2O3-SiO2-H2O and comparison with naturally occurring beryllian sapphirine and khmaralite. Part 1: Experiments, TEM, and XRD
- Intersite distribution of Fe2+ and Mg in the spinel (sensu stricto)–hercynite series by singlecrystal X-ray diffraction
- Structural relationships in (Mn1–xZnx)Mn2O4 (0 ≤ x ≤ 0.26): The “dragging effect” of the tetrahedron on the octahedron
- The grid-work texture of authigenic microcrystalline quartz in siliceous crust-type (SCT) mineralized horizons
- The crystal structure of vicanite-(Ce), a borosilicate showing an unusual (Si3B3O18)15– polyanion
- Submicrometer optical characterization of the grain boundary of optically active Cr3+ doped polycrystalline Al2O3 by near-field spectroscopy
- High-temperature, high-pressure optical spectroscopic study of ferric-iron-bearing tourmaline
- Infrared and Mössbauer study of Brazilian tourmalines from different geological environments
- Isothermal compression of staurolite: A single-crystal study
- Equation of state measurements of chlorite, pyrophyllite, and talc
- Structure change of Ca1–xSrxTiO3 perovskite with composition and pressure
- Mechanism of 2/1- to 3/2-mullite transformation at 1650 °C
- High-pressure deformation mechanism in scolecite: A combined computationalexperimental study
- Far infrared spectra of K+ in dioctahedral and trioctahedral mixed-layer minerals
- Ab initio quantum mechanical modeling of infrared vibrational frequencies of the OH group in dioctahedral phyllosilicates. Part I: Methods, results and comparison to experimental data
- Ab initio quantum mechanical modeling of infrared vibrational frequencies of the OH group in dioctahedral phyllosilicates. Part II: Main physical factors governing the OH vibrations
- On geological interpretations of crystal size distributions: Constant vs. proportionate growth
- Allabogdanite, (Fe,Ni)2P, a new mineral from the Onello meteorite: The occurrence and crystal structure
- Cristobalite inclusions in the Tatahouine achondrite: Implications for shock conditions
- Letters. Natural occurrence of Fe2SiO4 -spinel in the shocked Umbarger L6 chondrite
- Structural refinements of magnesite at very high pressure