A quick search of the BGS mineralogy and petrology collection records reveals this Tholeiitic Olivine-Bassalt 'Staffa-type' collected from the foreshore sill at east of Tavool by E B Bailey
A lot of people also used to go to the YMCA house at Tavool near Burg where the fossil tree is. That too is well worth seeing. Lol the list on Mull is endless as it is on Skye and other places :)