Microcline
Classification:
Microcline belongs to the feldspar group.
Synonyms/Trade Names:
Amazonit.
Chemistry/Composition:
K(AlSi3O8) .
Structure:
Silicon and aluminum atoms are tetrahedrally surrounded by oxygen atoms. These tetrahedra are linked and form four-membered rings, which are tilted out of the horizontal plane. The rings are bounded to chains which are linked by additional oxygen atoms. The structure can be described as a sequence of these layers formed by rings of tetrahedra which are placed one below the other. Large cavities are formed, which contain additional large ions in an irregular nine-fold configuration. The positions of the four silicon atoms are not symmetrical, and the bonding lengths between the silicon and oxygen atoms are different.
Crystallographic Constants:
8.580 12.970 7.220 90.640 115.930 87.680.
Crystal Group:
Triclinic.
Color:
White, gray or green.
Optical Properties:
nx=1.518-1.520 ny=1.522-1.524 nz=1.523-1.530.
Pleochroism:
In thin section, colorless and without Pleochroism.
Powder Diagram:
3.24 3.29 4.22 2.16 (19-932).
Natural Sources:
World-wide.
Varieties:
• Paracelsiane
Specification:
Paracelsiane is a barium containing feldspar.
Chemistry/Composition:
Ba(Al2Si2O8) .
Structure:
Silicon and aluminum atoms are tetrahedrally surrounded by oxygen atoms.
Crystallographic Constants:
8.580 9.583 9.080 90.000 90.000 90.000.
Crystal Group:
Orthorhombic.
Color:
Normally white, grayish, and seldom green.
Optical Properties:
Data not available.
Pleochroism:
Data not available.
Powder Diagram:
4.00 3.80 2.99 2.73 (10-352).
Natural Sources:
Great Britain (Wales), and Italy (Piemont).
Medical Importance:
Key Hazards:
Possibly fibrogenic, possibly mutagenic.
Involved Organs:
Probably lung.
Exposure/Epidemiology:
Exposure or technical use is not known.
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:
Associated specific findings are not known.
Lung Function:
Usually normal findings.
Bronchoalveolar Lavage:
Usually normal findings.
Pathology:
Gross:
The lungs are of normal color and consistency.
Histology:
The alveoli can contain an increased number of macrophages, and collections of brown dust particles may be seen in the lymphatic tissue.
Prognosis:
Usually good and without serious sequelae.
Additional Diseases:
None.
References:
search Pubmed for Microcline