Mayenite Ca₁₂Al₁₄O₃₃, is a rare cubic mineral of cubic symmetry, originally reported from Eifel

Eifel

The Eifel is a low mountain range in western Germany and eastern Belgium. It occupies parts of southwestern North Rhine-Westphalia, northwestern Rhineland-Palatinate and the south of the German-speaking Community of Belgium....

 volcanic complex (Germany). It is also found at pyrometamorphic sites: e.g., in the Hatrurim Formation

Hatrurim Formation

The Hatrurim Formation or mottled zone is a geologic formation in the Negev Desert in Israel and in western Jordan. It includes late Cretaceous to Eocene aged impure limestone along with coal bearing chalk and marl. The rocks have been subjected to pyrometamorphism resulting from combustion of...

 (Israel

Israel

The State of Israel is a parliamentary republic located in the Middle East, along the eastern shore of the Mediterranean Sea...

) and in some burned coal dumps. The formula can be written as [Ca₁₂Al₁₄O₃₂]O, which refers to the unique feature: anion diffusion process

Diffusion process

In probability theory, a branch of mathematics, a diffusion process is a solution to a stochastic differential equation. It is a continuous-time Markov process with continuous sample paths....

. Mayenite is also found as calcium aluminate in cement

Cement

In the most general sense of the word, a cement is a binder, a substance that sets and hardens independently, and can bind other materials together. The word "cement" traces to the Romans, who used the term opus caementicium to describe masonry resembling modern concrete that was made from crushed...

 where its formula is also written as 12 CaO · 7 Al₂O₃ , or C₁₂A₇ in the cement chemist notation

Cement chemist notation

Cement chemist notation was developed to simplify the formulas cement chemists use on a daily basis. It is a "short hand" way of writing the chemical formula of oxides of calcium, silicon, and various metals.-Abbreviations of oxides:...

.