I have never encountered a black based MacBeth tartan. Really, if you change the background of MacBeth to black, you'd have Black Stewart.

I suppose that the one pictured on the USA Kilts site (which I assume is Marton Mills) might be a navy blue that just shows up dark in the photo. Email or call Rocky and ask.

I know House of Edgar makes a MacBeth modern with a navy blue. But most other mills that weave this tartan produce it with a light blue background.

M