Bad soda-glass or that which has been kept for many years, tends to devitrify when worked.
"A Handbook of Laboratory Glass-Blowing"
Bernard D. Bolas
Long-buried glassy lavas devitrify, or pass to a stony condition, under the unceasing action of underground waters; but their flow lines and perlitic and spherulitic structures remain to tell of their original state.
"The Elements of Geology"
William Harmon Norton