This is an exceptional sculpture from Edmore, well-known for his lovely sculptures of fish. Such a gorgeous piece of stone - a fascinating internal colouration - and very hard and impermeable makes it suitable for outdoor display, perhaps by a pond?
'Butter jade' is the local Zimbabwean name for this beautiful and extremely hard variety of stone. It is not actually jade, nor is it a serpentine, and comes from near Birchenough Bridge in Zimbabwe and the Transvaal in South Africa. The internal structure of fine grains appears layered (usually cream and pale green), but when it is sculpted it behaves much more like flint!