What's the flame color of Calcium？

Flame tests are used to identify the presence of a relatively small number of metal ions in a compound. Not all metal ions give flame colours.

A flame is a constantly upward "moving" chemical reaction. The velocity is dependent on the flow rate of the gases entering the burner. There is an extensive upward motion (on Earth). In a gravity-less flame, the flame is round, still there is an upward movement. Now another important thing to note is that the Group II flame emission is not due their atoms but their hydroxides, such as CaOH. In an ordinary Bunsen burner flame you can expect "weird" molecules, which cannot exist in an ordinary bottle. The typical flame temperature is not hot enough to cause atomic excitation and completely break calcium compounds into calcium atoms. If this were true you would see a violet flame (422 nm) after introducing calcium. We see reddish color which is always contaminated with sodium's yellow color. 

Calcium salts produce an orange flame. However, the color may be muted, so it can be hard to distinguish between the yellow of sodium or gold of iron. The usual lab sample is calcium carbonate. If the specimen is not contaminated with sodium, you should get a nice orange color.