Vanadium comprises only 0.01% of the Earth's crust by weight.
Vanadium is capable of not only lowering the blood sugar of some diabetic-induced animal studies, but is also able to eliminate some of the diabetic side-effects in the heart and other systems. Severely induced rat studies (>500mg/dl) required only 8% of the insulin to reduce blood sugar to normal levels when taking oral vanadyl sulfate, when compared to those not taking vanadyl sulfate. Some of these studies have been confirmed with humans, and it is not uncommon to see vanadium or vandyl sulfate in supplements intended to control blood sugar.
Vanadium appears to have other biological functions, not all beneficial, some even toxic.
Because of Vanadium's potential for toxicity, daily doses exceeding 10mg/day are not recommended for long periods. Remember that this is for vanadium and it requires 32mg of vanadyl sulfate to reach 10mg of vanadium as it is only 31.25% vanadium.