Here's a breakdown:

* Limestone: This provides the calcium oxide (CaO) needed for the cement's chemical reactions. It's the main ingredient, making up about 75% of the mix.

* Clay: Clay provides silica (SiO2), alumina (Al2O3), and iron oxide (Fe2O3). These components are important for the formation of various minerals during the cement's production process.

These raw materials are ground together, then heated in a kiln to create clinker. The clinker is then mixed with gypsum, which controls the setting time of the cement.

While limestone and clay are the main ingredients, small amounts of other materials might be added depending on the specific cement type and desired properties.

Let me know if you have any other questions!