Angela â€” Stewart & Stewart p28 tells us that Davidson termed theirs Marble Glass
, continuing It should not be confused with glass made from iron slag, which is a different sort of glass altogether, and was the subject of much discussion in the Pottery Gazette
, providing references PG March 1881 Glass from Slag
, and PG July 1887 The use of refined slag in the manufacture of Glass
Simon Cottle never did discover precisely what Sowerby meant by their term Slag Glass
before publication, but did discover what it wasn't, as he found primary source material (advertisements, catalogues and price lists) that clearly distinguished it from their Malachites (purple, green, blue, brown, black, grey and red), Jet, Tortoiseshell, Ruby, Vitro-porcelain, Patent Queen's Ivory Ware, Blanc de Lait, Gold, Agate, Sorpini, Nugget, Rubine, Aesthetic Green, Opal, Rose Opalescent, Turquoise, Giallo and plain colours.