Halite

Halite, also known as sodium chloride or salt, finds its way into many places around the home. A rock composed primarily of halite is known as 'rock salt'. It is formed when seawater evaporates repeatedly over a long period of time.

You will probably find that, on a daily basis, you have lots of contact with salt.

Salt for breakfast

The more 'obvious' uses are in much of the food we eat. At breakfast we may consume small amounts of salt in our breakfast cereal and a little more in our toasted bread, which is perhaps topped with salted butter.

Chlorine, which can be produced from salt, is essential to the chemical industry where it is used in all manner of household products. For example, it essential for the production of plastics and polymers, such as PVC and nylon. Pause for thought as you brush your teeth. Your toothbrush may have a plastic handle and its nylon bristles brush your teeth clean.

Glass and paper

As you drink your orange juice out of a glass and maybe read a book or paper, you have again come into contact with products that are derived from salt i.e. caustic soda. Also called sodium hydroxide, caustic soda is a co-product of chlorine production and is used in the production of both glass and paper.

Before leaving the house for school or work we'll use salt again, by way of an ingredient, in our washing-up liquid or dishwasher tablets.

What does halite look like?

Salt sample


In the home

Salt is used widely as a food ingredient, as a flavour enhancer or preservative. It is also used in various household cleaning products.

Industrial uses or around the home

Salt is crucial to the chemical industry and it is also used in the manufacturing of thousands of other commodities including glass, paper, rubber, and textiles.

Key facts

Colour

Rock salt is typically colourless but may appear in a variety of different colours depending on the amount and type of impurities.

Rock or mineral?

Halite is the mineral everyone knows as salt.

Hard or soft?

Salt can be scratched with your fingernail.

Where is it mined?

The UK has huge resources of salt which mainly occur in England.

It is essential to our lives?

In food, we all need a little bit of sodium because it helps keep our body fluids at the right concentration and is needed for muscle and nerve activity.

Fun fact

Throughout history salt has been an important trading commodity. It is widely believed that Roman soldiers were paid salt rations or salt money, salarium argentum in Latin, which is where we get the English word ‘salary’ from.

Activity

Why do we use salt to 'melt' the ice on a frozen road or path?

Why not try this simple experiment below to see if you can find out how salt affects the freezing point of water?

  1. Fill two identical plastic cups with water
  2. Dissolve several tablespoons of salt into one of the cups and label it
  3. Put both containers into the freezer and check them every 2 to 3 hours;
  4. What did you notice?

Need more detail?

Download our salt factsheet