Agate is a set of micro-crystalline varieties of quartz. In fact, they are varieties of chalcedony that present bands of various colors with little contrast, which is due to the variation between the structure and the number of inclusions in the chalcedony, as well as its properties.
This gemstone is formed in volcanic rocks, whose size can vary from millimeters to several meters. Its main characteristic is that it presents a series of concentric bands of similar colors, opaque and translucent, which resemble the horizontal cut of a tree trunk. In addition, it can be found in various shapes, sizes and colors. It is a rock resistant to chemical reagents, and it is very hard.
However, some varieties are actually chalcedony with different inclusions, such as dendritic agate, mossy agate or mocha stone, landscape agate, onyx or onyx, fire agate, sardonyx or black onyx, holly blue agate, among others. These names are granted thanks to the colors and drawings that form their bands. The main deposits of agates are found in the United States, Brazil, Artigas department in Uruguay, Argentina, India and Madagascar.
From the outside and to the naked eye, it is very difficult to recognize an agate geode as they do not look like anything more than simple rocks, however, when you look deeper inside them, their interior shows very beautiful and distinctive crystal growth and formations. These Geode Agate crystals are usually made up of quartz or chalcedonic deposits, however various minerals such as calcite, celestite and dolomite are also found in other varieties of geodes.
Although it can be thought that the formation of agate geodes is very fast, it is much more complex since its formation takes millions of years. It is estimated that most of the geodetic specimens are more than 250 million years old. However, they are always hollow, no matter how old the stone is, they are never completely filled. Macro-crystalline quartz growths are generally transparent or translucent, with a vitreous luster, although they can occur in a wide range of vivid colors, depending on the type of crystals they contain.
Agate geodes usually develop in an ovular shape. They are then sliced to show the formation of the crystal. The side of the crystal is cut flat and lightly polished, leaving the rough exterior to act as a base for the stone and is not treated.
Its price is very variable, the smallest geodes can be priced between one to two dollars, but the largest samples cost several thousand dollars or more, it all depends on their growth, size and weight of the crystal. In jewelry, it is usually used for costume jewelry and small piecessince it gives them a delicate and beautiful touch, in addition, it is a very accessible stone, so the pieces of jewelry that contain it are really affordable and will give the wearer a unique touch without effort.