 ዝቅተኛ ግፊት እና ዝቅተኛ የሙቀት መጠን ላይ የሚችል የተረጋጋ ቢሆንም, ውኃ እንቅስቃሴ ለምሳሌ muscovite, pyrophyllite, ወይም kaolinite እንደ hydrous aluminosilicates የሚተካ ነው ያሉ ሁኔታዎች ሥር በቂ አብዛኛውን ጊዜ ከፍተኛ ነው.
Although potentially stable at lower pressure and low temperature, the activity of water is usually high enough under such conditions that it is replaced by hydrous aluminosilicates such as muscovite, pyrophyllite, or kaolinite.