Iodine has a certain lustre, like a metal, but it definitely is not a metal. It is quite volatile. This picture was taken on a hot summer day and one can clearly see a light violet vapor of iodine above the solid. Iodine keeps indefinitely, but it must be stored in a really tightly capped container. Iodine vapor, escaping from the container will ruin everything nearby.

A more permanent display of iodine is the following sample in a sealed glass sphere of approximately 6 cm diameter. The picture of this sphere was made on a normal day, with an ambient temperature of approximately 20 ºC, but even under those conditions, the purple vapor of the iodine can be observed, although only faintly.

When iodine is heated, then it sublimes and gives off purple vapor. This vapor is incredibly dark. The picture below shows the vapor of iodine in a tube, which is heated above the boiling point of iodine. The tube only has a diameter of 1.5 cm.

When the tube is allowed to cool down, then the color of the iodine vapor can be observed more easily. When the vapor has such a light purple color, then it is quite dilute.