It's an exceptionally well made handmade Alizarin and is the only brand I've experienced that actually matches the color effects of Rose Madder Genuine, an historic and very beautiful pigment. It is considered to be reasonably lightfast, and more stable and pure than any other brand over the past century. Here is the web link for Vasari
Alizarin Crimson .
I have most all the alizarin replacements too, and none of them really replaces the Vasari original.
Garth