This is a sharp, slender tremolite crystal with lustrous, striated prism faces. The crystal is a contact twin. In excellent condition, no damage. Ex Cal Graeber.
An interesting side note – a specimen on display at the Smithsonian Institution (labelled simply “Tanzania”) seems as though it is likely from the same occurrence.
A very fine crystal, and different from the Merelani ones we’ve seen coming out for a while.