Chemical properties of gemstones.
Gems, like all minerals, have a specific chemical composition. The elements occurring in them are generally common elements, which are common components of minerals.
The most common element is oxygen O. Except …
Diamonds Emeralds Rubies Sapphires
The chemical composition of the earth's crust.
Rocks that make up the earth's crust formed as a result of long-term, rock-forming processes that take place sometimes for millions of years. During their history, they have undergone various displacements, so, that some formed deep in the earth's crust are now on the surface of the earth and …
Formerly it was commonly judged, that the structure of the Earth is uniform, that its state of aggregation changes only under the pressure of the adjacent layers, turning initially into liquid, then into gassy. It was related to a fact that was known long ago, with as you advance …