In the chemical laboratory, why do scientists use a mortar and pestle?

Scientists use a mortar and pestle, either manual or machine powered, to decrease the size of the particulate being examined.

For example, I recently attended a lecture about an analytical chemist’s pursuance of an alternative to dusting powder for crime labs. In his presentation, he detailed that the initial substance he considered using wasn’t working because the particles were too big and weren’t mobile-his use of an automatic mortar and pestle allowed him to reduce the size of the particulate by nearly twenty times, allowing for the use of this particulate as dusting powder.