Oligoclase
Classification:
Oligoclase belongs to the feldspar group; for further information see under the heading albite.
Synonyms/Trade Names:
Albiklas, Natronfeldspat.
Chemistry/Composition:
a mixed crystalline formation containing 70-90% of albite and 10-30% of anorthite.
Structure:
Silicon and aluminum atoms are tetrahedrally surrounded by four oxygen atoms. These tetrahedra are linked and create four-membered rings, which are tilted out of the horizontal plane. The rings are bound to chains, and these rings are linked together by additional oxygen atoms. The structure can be described as a sequence of layers of these components, in which the rings of tetrahedra lie below each other. The structure contains large cavities, which include the additional bigger ions in an irregular nine-fold configuration. Two different forms of albite (low-temperature and high-temperature) occur naturally. Their Structure differs in the distribution of the aluminum and silicon atoms. A complete disordered distribution of these atoms is found in high-temperature albite.
Crystallographic Constants:
8.140 12.790 7.160 94.330 116.570 87.650.
Crystal Group:
Triclinic.
Color:
Normally colorless, sometimes grayishwhite, pink, or yellowish.
Optical Properties:
nx=1.52 9 n y = 1 .533 nz=1.539.
Pleochroism:
colorless.
Powder Diagram:
4.03 3.22 3.66 3.20 (19-1184 l)
3.19 4.03 3.21 3.66 ( 9466 l)
3.18 3.75 3.21 4.04 (10393 h)
3.21 3.18 4.03 3.75 (20572 h).
Natural Sources:
World-wide, large deposits exist in the Slo. Rep./Tsch. Rep., Italy (Trento), and Yugoslavia.
Varieties:
Varieties are numerous and described under the heading feldspars.
Medical Importance:
Key Hazards:
Possibly fibrogenic and carcinogenic.
Involved Organs:
Probably lung.
Exposure/Epidemiology:
Often used in ceramic and glass industries.
Thresholds:
In Germany, MAK 6 mg/m3.
Etiology/Pathophysiology:
Detailed data are not known.
Lung Diseases:
Associated specific diseases are not known; however, the mineral is listed by the ISO, i.e., possibly fibrogenic and mutagenic forms exist.
Clinical Presentation:
Associated specific symptoms are not known.
Radiology:
Exact data are not known; however, radiological changes such as diffuse interstitial densities and markings, pleural thickening, and small circumscribed nodules are assumed.
Lung Function:
Probably normal, mild restrictive changes may be noted.
Bronchoalveolar Lavage:
The mineral fibers can be analyzed in the lavage fluid.
Pathology:
Gross:
Exact data are not known; mild fibrotic changes are assumed.
Histology:
The inhaled mineral fibers are birefringent and deposited in the distant air spaces. Mild interstitial fibrosis is assumed as well as weak interstitial mononuclear inflammatory infiltrates.
Prognosis:
Usually good Prognosis with only slow progressive fibrosis, if any at all.
Additional Diseases:
None.
Remarks:
The adhesion of some bacterial strains to the mineral surface was found to correlate with its positive charge and hydrophobicity. The surface charge is one possible factor in cell damage, fibrosis, or cancer.
References:
search Pubmed for Oligoclase