Wooden Crystal Models - Orthorhombic

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Wooden Crystal Models - Orthorhombic


Geology, Mineralogy, and Crystallography


Physical Description

These crystal models are composed of a lightly colored Pearwood. Each model is precisely shaped with correct angles to illustrate various examples of seven different groups of crystal structures: isometric, tetragonal, hexagonal, orthorhombic, monoclinic, triclinic/trigonal, and twins. Some have been carefully sanded to represent natural curvature of face edges. Because each individual model is unique, the length varies from 3 to 7 centimeters, the width varies from 2 to 7 centimeters, and each has a unique weight. Some have identification numbers carved into them, which pertains to their original kit number given by the manufacturer. Some have hand written numbers in black ink on their flat faces, which identify the name of the crystal they represent.

Functional Description

These wooden crystal models were created as educational tools. The intent is to aid in the naming and identification of crystals by type. Each category of models is labeled in a separate box at the A.E. Seaman Mineral Museum. These models are still in use today at Michigan Technological University.

Dr. Friedrich Krantz developed a Rheinisches Mineralien-Kontor ("Rheinish mineral office") established by his uncle, Adam August Krantz, in 1833 into the world leader for making paper and wooden crystallographic models. The firm won numerous prizes at international expositions for the firm's exacting work and eventually had nearly 1,000 different mineral crystals to purchase.


Savannah de Luca


c. 1910


For forther infomration, see the Virtual Museum of the History of Mineralogy's page on Early Crystal Models and on pamphlets of the myriad models by Krantz at Krantz Wooden Crystal Models.




Physical object

Physical Dimensions

Length: 6 to 8cm Width: 3 to 6cm, variable




Dr. F. Kranz, Bonn, Germany


Some have identification numbers cut into them pertaining to each kit they originally came from, some have writing in ink on the flat faces that identify the mineral they model.


A.E. Seaman Mineral Museum


  • P. Tandy, "Crystallography and the geometric modelling of minerals: a reflection on the models in the Natural History Museum, London," The Geological Curator 6, no. 9 (1998): 333–338.
  • Wim Saeijs, "An Appraisal of Haüy's Wooden Crystal Models," Mineralogical Record39, no. 5 (2008): 385-396. [precursors to the Kranz types]

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Savannah de Luca, “Wooden Crystal Models - Orthorhombic,” Michigan Tech Inventory of Historic Scientific Instruments, accessed May 7, 2021, https://ihsi.omeka.net/items/show/170.