Glass crystal model


F. Krantz (ca. 1900)
Glass model of a monoclinic crystal (ca. 20 cm) from a series.
A small glued label indicates: "I | Dr. F. Krantz | Bonn a. Rh."

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.

private collection

the glass model as seen along the crystallographic b-axis
the glass model as seen perpendicular to the b-axis

top view of the model

detail of the label