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The size and number of stationary and quasi-stationary frictional contacts in rock analogues have been shown to increase with time due to deformation of asperities. This increase in the real area of contact, or contact'quantity', has been suggested to control friction in sliding contacts in rocks. Recent studies, however, find that contact'quality', eg, the density of chemical bonds on a frictional interface, may also be important in sliding friction. Here we present results of slide-hold-slide experiments on single crystals of quartz and halite conducted with a nanoindenter capable of applying a constant normal load and ramping to a lateral load that induces sliding. Indentations were first made with a diamond Berkovich tip to an indentation depth of 200 nm, after which sliding was induced at a velocity of 1 μm/s. The sliding velocity was then set to zero for holds 1, 10, 100 and 316 s in duration, followed by reloading to a sliding …