Crocidolite Crystals

Description

Since crystal lattice plane spacings are accurately known from x-ray measurements, they provide a good test of microscope stability and a calibration of magnification in the upper range of magnification of the instrument. Plane Spacing 0.9nm and 0.45nm – Asbestos Crocidolite. The 0.9nm spacing (020) will be found along the axis of the crocidolite fibers. The 0.45nm spacing appears at an angle of about 60° in suitable crystal orientations. Because of the hazards of asbestos, this sample is sandwiched between carbon and formvar films, than mounted onto a 3.05mm grid.

Lattice spacings 0.903 and 0.452nm
These crystals occur as long needles and display good diffraction patterns.  The planes parallel with the long axis of the crystals are of the 0.903nm spacing; the planes of spacing 0.452nm lie at about 60 degrees to this.
Some of the crystals in the preparation show a globular structure under electron irradiation, but a good proportion of the crystals appear unaffected by the beam, and yield clear lattice pictures