  Glass stability (GS) indicates the glass reluctance or ability to crystallise
upon heating; it can be characterised by several methods and parameters and is
frequently used to retrieve glass-forming ability (GFA) of corresponding
liquids as the case with which such liquids can be made crystal free via
melt-quenching. Here, GS has been determined for the first time on six
sub-alkaline glasses having complex (natural) compositions, the most widespread
and abundant on Earth. KT, KH, KW, KLL and w2 GS parameters increase linearly
and monotonically as a function of SiO2, with very high correlations. Moreover,
Tx values and GS parameters highly correlate with GFA via Rc (critical cooling
rate), previously determined with ex-situ cooling-induced experiments.
Therefore, GS scales with GFA for natural silicate compositions. In addition,
the in-situ Rc value of B100 measured with DSC results > 45 {\deg}C/min (> 2700
{\deg}C/h), broadly corroborating the Rc of about 150 {\deg}C/min (9000
{\deg}C/h) determined ex-situ. In turn, relevant solidification parameters on
heating or cooling can be obtained by DSC investigations also for chemically
complex (natural) systems, similar to simple silicate systems. These outcomes
are relevant for lavas or magmas that re-heat glass-bearing volcanic rocks, as
well as for fabricate glass-ceramic materials with desirable texture and
composition of phases starting from abundant and very cheap raw volcanic rocks.
