It is postulated that in stressed contact regions between silica grains the local
concentration of silica in solution might exceed the saturation level even though the
overall concentration of silica in solution is still below the saturation level. To recreate
this scenario under laboratory conditions, since the dissolution rate of silica is extremely
low, it would be far more efficient time-wise to have silica grains submerged in a
solution that already contains an elevated level of silica ions near the saturation level.
Thus when the silica cubes are under stress, a much smaller amount of silica dissolution
is needed to bring the local concentration of silica between grains higher than the
saturation level and to trigger precipitation of silica.