How much does calcium cost?
It is difficult to answer the question without a bit more clarification. Pure calcium bought from a chemical retailer such as Sigma-Aldrich will set you back ?96.10 for 5g or ?384.50 for the slightly larger amount of 25g. This price is only indicative of the retail market. As if you were going into a shop and buying it over a counter it won't necessarily reflect the wholesale value. It is however the cost you or I would pay if we wished to get hold of some. Pure calcium itself has relatively few uses and I certainly wouldn't recommend ingesting it as it is extremely reactive. As a result of this it can't be found naturally and occurs most commonly in sedimentary rocks in the minerals calcite, dolomite and gypsum. It also occurs in igneous and metamorphic rocks chiefly in the silicate minerals: plagioclase, amphiboles, pyroxenes and garnets. All of these naturally occurring calcium containing minerals can of course be mined and produced at a cost less than that of the pure calcium.
The least expensive (and quite an ideal way) to supplement calcium is to get calcium supplements called Dolomite, You need calcium and magnesium in a 2 to 1 ratio. Dolomite, a sedimentary calcium-magnesium carbonate mineral naturally comes in this ratio. Calcium from oyster shells are also quite good but more expensive -- this does not contain magnesium. Take 1000 mg of calcium before going to bed. Ralfcoder's recommendation are not bad. Gypsum is calcium sulfate, but I would hesitate at eating that. I would buy food-grade calcium sulfate from an Asian market (it is used for making Tofu) or a health-food store. Chalk is calcium carbonate, but some manufacturers add color to chalk. Since it is not food grade, they don't have to list the ingredients.
Depends on how you want it. You can get calcium supplements at the grocery store for maybe a few dollars for a small bottle. You can get sheets of gypsum board at the local building supply store or lumber yard for maybe $5 for a 4' x 8' sheet. That's mostly calcium with a paper coating. You can get chalk at any department store for maybe a dollar or two.
