The Canonical Biplot method is used to determine the magnitude of the effects on the chromatic coordinates (L*, a*, b*) and the parameter E*, where (L*, a*, b*) are the difference in the values of the sample after each aging cycle and the value of the untreated sample and E* = [(L*)(2) + (a*)(2) + (b*)(2)](1/2). We performed a study of the changes in color produced by two types of artificial aging procedures on four varieties of siliceous conglomerates from Zamora (Spain) that have traditionally been used in construction and later renovations in historical buildings in the zone. To accomplish this, 25 cycles of the following types of accelerated artificial aging were carried out: (a) freezing/thawing and cooling/heating (T1) and (b) combined freezing/thawing and cooling/heating + salt (phosphates) crystallization (T2). The results of the statistical study applied (Canonical Biplot) allowed us to differentiate the magnitude effect on the color of the surface brought about by T1 as compared with T2. These effects (p < 0.05) were observed in all but one (ochre conglomerate) of the varieties, but mainly in the variable governing red hue (a*) and yellow hue (b*). (c) 2012 Wiley Periodicals, Inc. Col Res Appl, 39, 82-87, 2014