Crystallization from the vapors

If winter in frosty weather suddenly open the window to the street from the damp and very hot heated room, then in those places where cold air rushes, snow begins to fall. And the reason for this is that there is a crystallization from the vapors of ice that has accumulated in the room. Therefore, in severe frost, "steam comes from the mouth". This crystallize with the white frost of a couple exhaled by a man. On the lid of a kettle or pots you can see how the water vapor, falling on a cold surface, thickens into a drop of liquid water. If temperature is below zero, then water vapor, cooling , passes not into the liquid, but immediately into a solid state, i.e., crystallization occurs from the vapors of ice. Clouds in the sky are nothing more than clusters of such ice crystals or drops of water formed from water vapor rising from the earth.

And the reason for this is that there is a crystallization from the vapors of ice that has accumulated in the room

In nature, crystallization can occur from vapors not only of ice, but also of other substances. The process of crystallization from vapors can be constantly seen in huge, "natural laboratories" - volcanoes. Temporarily idle and quite extinct volcanoes are often said to "smoke" - from them continuous streams of smoke: these are the substances that reached the surface of the earth in the form of vapors, and not melts or solutions. Standing out from volcano craters or from cracks near volcanoes, the vapor settles on the walls and on the ground, condensing, solidifying and crystallizing. So crystalline crusts are formed, and raids are native sulfur, metals, rock salt and other minerals.

It is easy to observe crystallization from vapors iodine with the formation of crystallites. To do this, we put two or three crystals of iodine in a test tube and heat on the flame that place of the test tube, where they lie. You can see that the crystals of iodine do not melt, but immediately evaporate, forming dark brown iodine vapor. Then, in a cold place in the test tube, a dark bloom will appear. If you look at the magnifying glass, you can consider a lot of small crystals of iodine. Crystallization occurred from iodine vapors, which, without passing into the liquid state, passed directly to the solid - crystalline.

A case is known when, during the eruption of Vesuvius volcano in Italy, a vein of crystalline hematite (iron shine) with a thickness of a meter was formed from the vapors within ten days. The same crystallization from the vapor of molten metal is observed on the walls of metallurgical furnaces.