The stunning cone 10R Ravenscrag bamboo glaze (GR10-J plus 0.5% iron oxide) on a Grolleg porcelain. Up close it can feel and look like a fine wood surface (when used on a porcelain). The cone 10 recipes page at Ravenscrag.com has more info.
GR10-J1 - Ravenscrag Cone 10R Bamboo Matte
Plainsman Cone 10R Ravenscrag Slip based glaze. It can be found among others at http://ravenscrag.com.
A term used in ceramic to express the degree to which an item is safe and stands up to everyday use. Functionality embodies strength, hardness, resistance to acid attack and thermal shock, etc.