is limestone a kind of minerals?

limestone (or called marble chips) is calcium carbonate CaCO3, it is a kind of chemical which is use for absorbing the moisture, you may come across in some experiment later in your chemistry lesson.

Limestone and chalk are sedimentary rocks. Marble is a metamorphic rock. They are rocks which contain the same mineral - calcite.
So limestone, chalk, marble are not minerals. Calcite is a mineral.
Because a mineral is a naturally occuring solid with a define crystalline structure and chemical composition; a rock is a solid mass of a mineral or a mixture of minerals.
Eg: Ice is a mineral but water isn't.