Butterfly walk

On my walk today I saw the most incredible butterfly.  I cannot find a photo online - it was black and/or dark, dark green.  On the back of it's wings there was indigo blue and bright red.  It had a swallowtail shape (I think that is what it is called) and was the size of a large (4X6") postcard- perhaps a bit bigger.  I felt so fortunate to see it. 

This butterfly is called the Purple Sapphire - it could be similar or the same.  I only saw it in flight.