Natural latex is a resin extracted from the rubber tree (Hevea brasiliensis).  Latex mattresses can be made using 100% natural resin, varying blends of natural and cloned synthetic latex, or 100% synthetic latex.
Natural latex is more elastic, lighter and stronger.
Synthetic latex is denser and harder, but more homogeneous and stable.
During the production of latex foam, substances such as talc or gypsum may be added. They are much cheaper than latex, which cuts the cost but gives a poorer quality end product.
Most latex mattresses on the market today contain no more than 25% natural latex.
When the blend has been obtained, a series of natural substances, such as sulphur, are added to “vulcanise” the latex and make it more elastic.  With the addition of soap (foaming agents) and air the emulsion becomes foam.