The Chemistry of Climbing Chalk


Climbing chalk can come in many different chunkinesses, in block form, or even as a liquid. Climbing chalk, or magnesium carbonate (MgCO3), has been used by climbers, lifters, gymnasts and many other athletes to reduce moisture and increase friction. I’ve been rock climbing for a while, and have used many different brands and textures of chalk and I’ve always wondered what makes good chalk good. As a climber, I use chalk very frequently and it greatly improves my and every other climbers climbing ability.

Composition of ...Pure climbing chalk is magnesium carbonate, but comes from magnesite which is magnesium carbonate mixed with iron (II) and carbonate crystals.

Main Chemicals, Compounds, Components

magnesium is number 12 on the periodic table, and has 2 valence electrons, so it wants to lose 2 electrons. Carbonate CO3 wants to gain 2 electrons. Magnesium carbonate is relatively insoluble in water, and because sweat is mainly composed of water, putting magnesium carbonate on your hands keeps hands sweat free.

Chemistry's Role

Climbing chalk comes from magnesite which is MgCO3 mixed with iron (II) and carbonate crystals. Magnesite is heated to get rid of the iron and carbonate, but the heat doesn’t break the bond between the magnesium and the carbonate because it is an ionic bond. An ionic bond is a bond between two oppositely charged molecules, and is extremely hard to break apart. Once the magnesite is purified of the iron and carbonate crystals, it is in a solid block. The block can then be used in the block form, or it can be crushed up into finely crushed powder. MgCO3 can also be made from a reaction in the laboratory between a soluble magnesium salt, such as magnesium chloride, and sodium bicarbonate. The reaction between the two produces magnesium carbonate (climbing chalk), sodium chloride (table salt), water, and carbon dioxide. MgCO3 is insoluble in water because its lattice energy, or the energy needed to break an ions lattice structure is greater than the hydration energy, or the energy released when ions are hydrated in a solution, so when MgCO3 is put in water, the energy released isn’t enough to break up the magnesium and carbonate. Because MgCO3 is insoluble in water and sweat is manly water, MgCO3 will keep hands from getting sweaty.

Background Research

Climbing chalk is a pure compound of magnesium carbonate. It is mined from Magnesite, an opaque rock that is a mixture of magnesium carbonate mixed with iron and carbonate crystals. There are many magnesite mines around the world, but one of the largest is in Australia. Chalk was first introduced in 1955 by John Gill who was also the first person to climb a V8 and V9.


how Chalk is made from magnesite

forms of chalk

liquid chalk info

info about chalk

how chalk works

more about liquid chalk

composition of sweat

About the Author

Alex Sutherland is currently a junior at senior high in Billings Montana. He plans on going to MSU Bozeman after senior year and to study engineering. He is in cross country and enjoys rock climbing and paintball, but does not enjoy spending hours on chemistry homework.