SiO2 pseudomorphs after Wavellite
Mauldin Mountain
Montgomery County Quarry
Montgomery County, Arkansas.
ex Henry Delinde collection.
These 1.5 inch diameter specimens represent a common "mineral misnomer" specimen type from Montgomery County, Arkansas. This is what used to be a massive Wavellite sphere that was replaced by SiO2 overtime. The general mineral community commonly refers to these as Crandallite pseudomorphs...they are not! We have sent several samples to be lab tested and they are all SiO2 pseudomorphs after Wavellite. The exact variety of SiO2 we did not determine. Although John Betts had some sent through definitive x ray diffraction testing, and they came back as "Opal-CT and Quartz var. Chalcedony mixtures"....not Crandallite! There are probably thousands upon thousands of mislabeled specimens of this type and from this locale out there. Time to update old labels :)