Thin sections related to pyrotechnology in Bronze Age Sicily

The arrival of new thin sections is always exciting, but always daunting at the same time. Sediment micromorphology has to be one of the more challenging geoarchaeological techniques, simply because of the huge variety in the types of material you can encounter, and a deposit from one site never quite looks the same as one from another, even when they are related to similar activities. The samples from Case Bastione were collected to investigate formation processes and activities of a number of features in the Bronze Age settlement, including a large 'burnt' layer, and some strange pit deposits. The most striking thing about all the samples is the ubiquitous presence of these teeny tiny little creatures - my educated guess is that these are tiny foraminifera of some sort, present within limestone/chalk or another carbonate material (I need to do some research on Sicilian geology!). What is slightly confusing is the presence of a spherulite like appearance within the shells in cross polarised light. This isn't something I have seen before and I am not entirely sure what it means!