I had so many african violets I had to give them to my Mom. I kept some variegated leaved ones. A few I was partial too! I start them from leaves all the time. I get that root hormone grower. I also use those empty medicine bottles. Or any small glass container where the leaf will stay in place. I break the leaf off, dip it in the grower and put in water. You will have roots in a few days.
I just did one not long ago. And I see 3 white leaves comeing up.