Monthly Tech-Tip from Tony Hansen SignUp

No tracking! No ads!That's why this page loads quickly!

50-250C | 80C-250C | 120C | 150C | 180C | 185C | 200C | 200C-1000C | 200C-450C | | 250C-370C | 260C | 290C | 300C-330C | 300C | 370-950C | 400C-600C | 400C | 425C-650C | 480C-600C | 500C-600C | 512C | 535C | 540C-600C | 650C-900C | 700F | 750C-1000C | 750-850 | 800C-1100C | 850-950 | 850C | 850C+ | 900-1000 | 900C | 990C | 1025-1325 | 1025C+ | 1050C | 1050C | 1082C | 1100C+ | 1100C | 1100C | 1300C | 1325C | 1330C | 1360C | 1400F | 1400F | 1418C-1428C | 1420C | 1500F | 1550C | 1565C | 1600F-1650F | 1650F | 1785C | 1800F | 1950F-2050F | 1990C | 2300C | 2320C | 2750F


Cristobalite inversion (alpha/beta)

Occurs in cooling clay bodies at around 225C (and on heat-up for vitreous ware being refired). It is accompanied by a sudden volume change. Cristobalite, a less stable form of crystalline quartz, can be present in the matrix of stoneware clays where sufficient fine quartz, time and temperature (above 1100C) are available during firing. The range of temperatures is given here because charts that plot the expansion against temperature vary with different sources. In addition variations in temperature in the cross section of ware changes in volume occur as waves across a piece and can crack it. Thus if one side of a piece is 250C and the other 200C, the inversion and associated volume change are happening in the center of the piece. Less cristobalite is formed in faster firings and in more vitreous clay bodies where the feldspar takes the small quartz grains into solution.

Related Information


Glossary Cristobalite Inversion
In ceramics, cristobalite is a form (polymorph) of silica. During firing quartz particles in porcelain can convert to cristobalite. This has implications on the thermal expansion of the fired matrix.
Temperatures Quartz inversion (alpha-beta) (540C-600C)

By Tony Hansen

Tell Us How to Improve This Page

Or ask a question and we will alter this page to better answer it.

Email Address





Leave the following empty, All Rights Reserved
Privacy Policy