Table salt is your everyday white granular salt found in most kitchens and is almost pure sodium chloride. It can be harvested from the sea, but is generally mined from inland deposits. It is then refined to remove other minerals. Often table salt is ‘iodized’, which refers to the fact that the manufacturer has added a small amount of potassium iodide to it. Iodine is important in preventing insufficient production of thyroid hormones.
Rock salt is course and usually mined from underground salt deposits. It is unrefined, and contains more minerals, and often, more impurities than table salt. The crystals are large and hard and ideal to use in a salt grinder.
Sea salt is a broad term that generally refers to unrefined salt obtained from the sea. It comes in many forms, granules, large crystals and flakes. It is considered healthier than table salt since it is not processed with artificial chemicals. But, although it contains a small amount of iodine, it does not contain as much as iodized table salt.
Murray River Salt
The last few years have seen a rise in the popularity of gourmet salts, including this Australian variety, which is pumped from underground brines in the Murray Darling Basin in inland Victoria and New South Wales. The water is pumped into areas affected by salinity, which were previously unusable. Here, the regions low rainfall and high evaporation have created the right conditions for crystallisation. Like sea salt, the water evaporates naturally before the salt is harvested and no chemicals are used. A red pigment, carotene, is secreted from the algae, giving the salt its pink colour.