Ah...Magnesite
It takes a dye well.
About 12 years ago it took the place of howlite
as the dyed cheap stone.

 
Magnesite is a mineral with the chemical formula MgCO3 (magnesium carbonate).
Mixed crystals of iron II carbonate and magnesite (mixed crystals known as ankerite) possess a layered structure:
monolayers of carbonate groups alternate with magnesium monolayers as well as iron II carbonate monolayers.
Manganese, cobalt and nickel may also occur in small amounts.
There...does that help?