In its loose form it's known as the widely used talcum powder. It's the softest known mineral & listed as 1 on the Mohs hardness scale. It can be easily scratched by a fingernail. The crystal form is very rare.
Stilbite - Nice little thumbnail with spherical clusters to of lustrous light honey-colored Stilbite that display nice radial cross sections. This and many more mineral specimens are available for sale at Dakota Matrix Minerals.