Chemical rocks forms when minerals that are dissolved in a solution crystallize. Limestone can form when calcite that is dissolved in lakes, seas, or underground water comes out of solution and forms crystals. They can also form from mineral deposits left when seas or lakes evaporate. Water (H2O) is polar because of the bent shape of the molecule. The shape means most of the negative charge from the oxygen on side of the molecule and the positive charge of the hydrogen atoms is on the other side of the molecule. This is an example of polar covalent chemical bonding.

Interesting, Rk Naresh answers a question by Rk Naresh. Hmmmm!

Generally, inorganic detrital(Sedimentary) rocks containing soluble minerals such as calcite(CaCO3) and Gypsum(CaSO4.2H2O) are formed when minerals that are dissolved in a solution crystallize. A water molecule contains two poles, with a partially positive charge on the hydrogen pole (side) and a partially negative charge on the oxygen pole (side), due to the uneven distribution of electrons among the atoms and the asymmetrical form of the molecule. This happens because of the large difference in the electronegativity of Oxygen and Hydrogen. Due to the polar nature of the solvent, its tendency to dissolve inorganic compound increases resulting in the reducing crystallization rate. So addition of impurities or decreasing temperature or increasing pressure might increase the rate of crystallization of minerals.

Dear Brian P.J. Stevens and Dhiroj Thapa thank you for your contribution to the discussion

Water is a polar molecule due to the unequal distribution of its electron density. Because there is a difference in electro negativity between hydrogen and oxygen, this shows that water is a polar molecule. The shape of a molecule and the polarity of its bonds determine the overall polarity of that molecule. A molecule that contains polar bonds might not have any overall polarity, depending upon its shape. The two hydrogen atoms and one oxygen atom within water molecules (H2O) form polar covalent bonds. While there is no net charge to a water molecule, the polarity of water creates a slightly positive charge on hydrogen and a slightly negative charge on oxygen, contributing to water's properties of attraction.A water molecule is polar because there is an uneven distribution of electrons between the oxygen and hydrogen atoms. Water is a "polar" molecule, meaning that there is an uneven distribution of electron density. Water has a partial negative charge near the oxygen atom due the unshared pairs of electrons, and partial positive charges near the hydrogen atoms. Sedimentary Rock Formation when minerals dissolved in water crystallize between sediment grains, the process is called cementation. Mineral cement holds the grains together. Igneous rocks are rocks formed from the crystallization of a liquid (molten rock). Igneous rocks may be divided into two categories. Intrusive or plutonic rocks crystallize from magma beneath the earth's surface. Extrusive or volcanic rocks crystallize from lava at the earth's surface. Crystalline rock, any rock composed entirely of crystallized minerals without glassy matter. Intrusive igneous rocks those that congeal at depth are virtually always crystalline, whereas extrusive igneous rocks, or volcanic rocks, may be partly to entirely glassy. Crystal form refers to the geometric shape of mineral crystals. Crystal form is caused by the symmetrical, three-dimensional arrangement of atoms inside the mineral. Not all minerals form perfect visible crystal shapes. Some crystals are too small to see. Metamorphic rocks were once igneous or sedimentary rocks, but have been changed as a result of intense heat and/or pressure within the Earth's crust. They are crystalline and often have a “squashed” texture.