Why doesn't the whole volcanic cone appear black? Cooled lava looks black, but why the whole volcano, even near crater, doesn't always appear black like cooled lava?
The cooled lava might be covered by ashes. So depending of the amount of ashes and the wind you might have a black volcano or a gray volcano. Many volcanoes are formed by layers of lava and ash.

https://en.wikipedia.org/wiki/Volcano#/media/File:Volcano_scheme.svg