Garnet var. Grossular - Elongated Crystals
Based on a specimen from Turin, Piedmont, Italy.
Surprisingly, some of the most unique crystals I have modeled have been garnets. The odd garnet described here and the complex tsavorite shown here are examples. This is another. The garnet crystal that this model is based on is elongated along one of its fourfold axes, making it look tetragonal instead of isometric. It really doesn’t look much like a garnet at all, and it took a little while for me to convince myself that that’s what it was!
The specimen is a nice illustration of one of the fundamental laws of crystallography - the law of constancy of interfacial angles. Even though the crystal is quite elongated in one direction, the angles between the individual faces are exactly what they would be in an undistorted crystal. Accurate measurement of these angles would allow a crystallographer to recognize the crystal for what it is - a combination of a trapezohedron and dodecahedron. Below you can see a view down the fourfold axis at the top of the elongated model next to the same view of an undistorted crystal. Although the edge lengths and face sizes are different due to distortion, the angles are the same.
The whole specimen is basically a large cluster of these elongated crystals. A photo of the nicest crystal is shown above, but there are many others, all elongated in the same direction. I’d love to be able to explain how these unusual garnet crystals originated, but the truth is I don’t know. I’ve seen one hypothesis that they might be faden garnets. Unfortunately, my specimen is coated with something that makes it impossible to see any internal structure, so any faden inside remains well hidden.
I like using really special wood in models with large faces, because it gives me a chance to show off the kind of neat grain or color variation that would be ruined if it was chopped up into little pieces for tiny faces. This particular piece of yellowheart is the nicest I’ve seen, with all the colors of a sunset. I had been saving it for something special, and I think it looks beautiful here.
Model details: 12" tip to tip. Trapezohedron faces are yellowheart, and dodecahedron faces are padauk.
Specimen details: Elongated garnet var. grossular. Turin, Piedmont, Italy. 8mm crystal.