The ultramarine analogs of various colors have been prepared by calcination (mostly at 800degreesC) of the mixtures of zeolite A and sodium polysulfides or elemental sulfur and sodium carbonate. The color and structure of the products depend very much on alkalinity of the mixture. Low alkalinity leads to green products with retained LTA structure. Blue products with SOD structure are attained at high alkalinity. Alkalinity affects also the weight loss on heating (i.e. emission of volatile compounds) as well as the amount of salts removed on washing. (C) 2004 Elsevier B.V. All rights reserved.