Large, sharp, and well-formed, these three Hauerite crystals ON MATRIX are from the best of species locality (a historic find of the mid 1800s). Note the unusual complex crystal habit - basically, the two larger crystals are truncated octahedrons and the smaller crystal is an octahedron with the smallest amount of cubic modification. The largest Hauerite is a significant 1.6 cm across. This is a top-notch, old-time example of the species and locality. They are almost never seen in matrix today because the matrix was a decomposed kaolinite and incredible care must be taken to preserve it when collecting the material - not commonly done in the mid 1800s. The matrix is similar, in fact, to the matrix of the famous Boleite locale in Mexico. It must be stabilized soon after collecting, to help hold it together. This piece came to us dry and friable, and we restabilized it with a very small amount of diluted glue, soaking into the porous matrix. This is previously from the collection of the University of Naples. It is one of the most important historic pieces in this well-known collection. Pictured in the Mineralogical Record, Vol. 54, No. 4 (July-August 2023).