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