What is a picrite in geology ?

A picrite is an ultrabasic volcanic rock of black color, with a microlitic or doleritic texture, characterized by a great abundance of olivine (from 30 to 50%) and titaniferous augite (about 30%), with as accessory minerals : brown amphibole , labrador-bytownite, biotite or phlogopite, and sometimes analcime. These rocks usually belong to ultrabasic complexes, or form veins in other basic rocks.