This is a special and rare paint, very hard to come by, I don't know of anyone else making it. The pigment for this paint is sourced from peat bogs in Russia.
Until relatively recently painters throughout history have always deeply respected the colour blue as it is very hard to find natural sources of it. Hence the use of Lapis Lazuli which for a long time came from just one mine in Afghanistan and yet found it's way to the Italian and Northern Renaissances and the ancient Egyptians.
This is a natural blue earth and in my opinion equally as special as Lapis.
In masstone it is very dark, similar to a natural indigo. It has a lovely feel, ground perfectly you can feel the pigment particles but they are not obtrusive, I suspect pigment size is important it maintaining a good rich hue. It feels earthy.
It is a gentle tinter but this for me is where it shines, it makes smokey blue tints with a distinct earthy depth, it has the slightest green undertones. The tints get more beautiful the higher value they are (the more white added) when muted, gentle blue greys are created.
This paint would work very well on a landscape palette.
It is expensive however maybe to help understand why below is a wonderful video showing just some of the work involved in preparing this pigment, never mind sourcing it (very labour intensive) and making it into paint.
Pigment - Vivianite/Blue Ochre
Binder - Cold Pressed Linseed Oil
Opacity - Opaque
Drying Time - Average