With the models in its Sortoscope series, the Firm Nossigem Lab Services is specializing in the efficient grading of diamonds and gemstones. The main application of the Sortoscope models is batch control of diamonds and gemstones by means of a support rail (Fig 159). The Sortoscope procedure uses a specially developed illumination technique which makes it possible to examine diamonds and other gemstones free, to a large extent, from reflections, and without 'the need to clamp stones individually; as is the case with traditional dark-field illumination. The stones to be examined lie loose in a support rail, and illumination is produced from below through the rail (Fig 160). The rail acts simultaneously as a diffuser. The result is a soft light field with very low reflectivity, and this also permits examination of large batches under very pleasant and relaxing working conditions. Entire batches of the stones to be examined are simply poured out of the delivery package or a small scoop. The rail profile is built so that a slight shaking cross- or lengthwise will tilt most of the stones to a 'position in which their tables are upwards. While they are being examined, the stones are sorted through the microscope from the support rail through a distance of only a few millimeters into small scoops located behind the rail and in the viewing field of the microscope, and from there they are poured directly back into the delivery packages, so that while no stone need to be handled individually it can nevertheless be quickly sorted.
Fig 159 SORTOSCOPE for the sorting and grading of small brilliants. (top)
Fig 160 The main application of the SORTOSCOPE is batch control of brilliants.(left)