Sandy ware

Sandy ware is a type of medieval (and earlier) pottery with enough quartz sand mixed in with the clay for it to be visible in the fabric of the pot. The sand acted as a temper which helped bind the clay together, and keep the finished pot from cracking while being dried and subsequently fired.

Medieval sandy ware, North Yorkshire

Shelly-sandy ware, or simply shelly ware, used both sand and ground-up shell (shells that have been ground - reduced to small particles or powder by crushing it) as temper. Medieval shelly-sandy ware has a date range 11th to 15th century. The fabric is always dark grey with brown oxidised surfaces.[1]