Actually people tend to go overboard with calcium because of all the media hype. Excess calcium can cause muscle cramping, high blood pressure, constipation, restless legs and other muscle spasms, incontinence, asthmatic symptoms, etc. Calcium MUST be balanced with sufficient magnesium to prevent these side effects.

The form of calcium is also important. Calcium carbonate, including coral and Tums, is garbage. It neutralizes the stomach acid decreasing the absorption of the calcium and other minerals, as well as some vitamins needed for bone strength. It is the cheapest form of calcium though, and so is found in many supplements. And taken with oxalic sources, such as chocolate, spinach, kale, purslane, and rhubarb the calcium binds forming insoluble and therefore unusable calcium oxalate. So the new calcium chocolate chews on the market are nothing more than a gimmick. Stick to acidified forms of calcium such as calcium malate or citrate

Milk is also a bad source of calcium since the protein in milk blocks calcium absorption. To make things worse the phosphorus in milk leads to a release of parathyroid hormone, which in turn breaks bone tissue down. The Sugar and protein can also lead to bone loss through their acid formation. This is why the two largest milk consumers in the world, the US and Finland, also have the highest osteoporosis rates in the world. Chocolate milk is even worse, again due to the oxalic acid content of the chocolate.

Silica is actually significantly more important than calcium for bone health. Then there is vitamin C, sulfur, and boron. Then comes calcium, magnesium, phosphorus, strontium, fluoride (natural), manganese, copper, zinc, vitamins A, D, E, and K, and essential fatty acids. Calcium by itself is not going to build bones, and is just going to cause a lot of problems.