Encara no tenim significats per a "compose of carbonate".
1It is very hard, being composed of carbonate of lime, and will last for ages.
2The skeleton of calcareous sponges consists of a number of spicules composed of carbonate of lime.
3The efflorescing matter is composed of carbonate of soda, chloride of sodium, and biborate of soda.
4They include, first of all, the foraminifera, which usually have shells composed of carbonate of lime.