The building is a masterpiece in sculpture in Maltese globigerina limestone.
From the en.wikipedia.org
The softer globigerina was used for decorative elements within the temples, usually carvings.
From the en.wikipedia.org
Globigerina limestone is the second oldest rock on Malta, outcropping over approximately 70% of the area of the islands.
From the en.wikipedia.org
The picture shows a type of stone known as a globigerina limestone, which is the traditional building stone of choice in Malta and Gozo.
From the newscientist.com
More examples
Marine protozoan having a rounded shell with spiny processes
The Globigerinida are a common group of foraminiferans that are found as marine plankton (other groups are primarily benthic). They produce hyaline calcareous tests, and are known as fossils from the Jurassic period onwards. ...