21. Stoneware may be vitrified or semi-vitrified , the latter type would not be impermeable without glaze. 22. Vitrification is a particularly attractive immobilization route because of the high chemical durability of the vitrified glass product. 23. Vitrified forts such as Castle Hill are rarely found in England, and are more usual in Scotland.24. The roofs were covered vitrified tile over book tile while the dome was covered with gilt glass tiles. 25. The excavations also found vitrified rock, possibly indicating the island was once occupied by a vitrified fort. 26. The excavations also found vitrified rock, possibly indicating the island was once occupied by a vitrified fort. 27. Typically, they only survive as earthworks today, although remains of vitrified forts are found throughout Scotland. 28. Other similarly-sized vitrified forts within the area include Dun Evan, Dun Finlay and Dun Davie. 29. Each block of " vitrified " waste each weighs 490 kilograms ( 1, 000 pounds ). 30. Twenty-First Century Medicine has vitrified a rabbit kidney to-135 �C with their proprietary vitrification cocktail.
