NaCa2Ti2Si6O18

NaCa2Ti2Si6O18 is a complex oxide mineral that belongs to the group of silicate minerals. It was first discovered in the Khibina alkaline massif in the Kola Peninsula, Russia. The mineral is characterized by its unique chemical composition, which includes sodium (Na), calcium (Ca), titanium (Ti), silicon (Si), and oxygen (O). Its crystal structure is monoclinic, and it typically forms as small, dark brown to black crystals or granular masses.

The mineral is notable for its high titanium content, which makes it of interest to geologists and mineralogists studying the formation and evolution of alkaline igneous rocks. NaCa2Ti2Si6O18 is often found in association with other titanium-rich minerals such as aegirine and astrophyllite. It has also been reported from other alkaline igneous complexes around the world, including those in Canada, Greenland, and the United States.

The mineral's name is derived from its chemical formula, which reflects the presence of sodium, calcium, titanium, silicon, and oxygen in its structure. The mineral's physical properties, such as its hardness and density, are consistent with those of other complex oxide minerals. However, its exact optical properties and specific gravity have not been extensively studied.

Despite its relatively rare occurrence, NaCa2Ti2Si6O18 is an important mineral for understanding the petrogenesis of alkaline igneous rocks. Its presence in these rocks provides insights into the processes that lead to the formation of titanium-rich minerals in alkaline environments. Further research on this mineral may contribute to a better understanding of the geological history of alkaline igneous complexes and the conditions under which they form.