1. Earthenware: Any vessel which in its unglazed state would NOT hold a liquid.  It is always opaque but with varying degrees of coarseness and fineness.  Examples are “Majolica”, “Faience” and “Delft” and are all decorative, tin-glazed earthenware.  It is sometimes called Terracotta.

2. Stoneware:  Any vessel which in its unglazed state WOULD hold a liquid.  In addition to clay, a feldspar is used as a fusing agent.  When glazed, salt is the most typical glaze.  Examples are early German and English stoneware, Staffordshire salt glaze, Wedgwood Jasper and Basalt wares, and
19thc Ironstone and Feldspar wares.

3. Porcelain: “Hard Paste” is made of a certain natural china clay (Kaolin) and a natural chinastone (petuntse a type of Feldspar) as a fusing agent.  It is called “hard” because it is fired at high temperatures, 1400° C or 2552° F.  It is sometimes referred to as the “true” porcelain.

“Soft Paste” is made of substitute clays or chalk and fusing elements.  The ingredients varied widely but always included clay, most often ball clay, combined with ground glass, bone ash, soapstone or quartz.  The fusing agent usually was a “frit” or mixture of ground-up glass in place of natural chinastone.  It is not as strong a Hard Paste and fires at a much lower kiln temperature.  The earlier pieces were much more prone to scratching/breaking or shattering when hot liquid was suddenly poured into them.  It is sometimes referred to as “artificial” porcelain.