Geoscience Reference
In-Depth Information
354
355
354
Historic English terracotta showing a matrix of
fired brick clay with grog comprising particles of
previously fired clay (rounded particles); PPT, ×35.
(Courtesy of Barry J Hunt.)
355
Close view of English terracotta manufactured in
1905 showing an arrowhead-shaped crystal of
tridymite (grey); XPT, ×300. (Courtesy of Barry J Hunt.)
356
357
356
A large ceramic grog pellet in terracotta; PPT,
×35.
357
Ceramic tile with a fired clay base (left) comprising
vitified clay (brown) with angular inclusions of ground
quartz (white). Opaque underglaze applied to clay base
(grey) includes fine particles of a crushed aggregate for
colour. The outer glaze (right) is glassy and transparent
(white); PPT, ×150.
358
359
358
Same view as
357
in cross-polarized light. The
fired clay base appears red with grey/white quartz
inclusions (left). The underglaze containing fine-
grained colouring aggregate appears grey and the
glassy outer glaze is isotropic (black, right); XPT, ×35.
359
Ceramic floor tile (left) and tile adhesive (right).
The tile consists of fired-clay matrix (reddish-brown)
with very fine quartz sand inclusions (white). The
adhesive comprises natural sand fine aggregate (white)
bound by a cement matrix consisting of HAC mixed
with Portland cement (brown); PPT, ×75.
