Krantz glass model (ca. 1900?)
Glass model of a monoclinic crystal (ca. 20 cm) from a
A small glued label indicates: "I | Dr. F. Krantz | Bonn
Internal silk threads materialize the crystallographic
axes and illustrate with the corresponding colours the
dispersion of the optic axes and of the acute bisectrix
for blue, yellow and red light.
Collection: private collection
the glass model as seen along the crystallographic b-axis (left
image) and perpendicular to this direction (image at the right).
top view of the model with detail of the label