Mortons plain or white salt blocks are compressed from vacuum granulated salt, fine solar salt or fine rock salt. The appearance is white to crystalline with a smooth glossy surface. There are no additives. Plain agricultural salt blocks are used primarily for animal feeding.

Mortons iOFIXTIodized Salt Blocks are fortified with nutritional iodine provided by calcium periodate, which is water insoluble and does not leach from blocks exposed to high humidity or rain. When ingested by animals, it is readily solubilized by rumen microbial action or by stomach acidity.