Stones with banding are very unique and beautiful.
The striking bands are often from fascinating inclusions and geothermal conditions and can create exotic patterns on different stones.
Here’s a list of different stones with banding, where they’re often found, and how you can tell them apart.
10 Types of Rocks That Have Banding
First of all, what is banding?
Banding is a discoloration in a stone that can be caused by a variety of different factors.
This could be slight change in chemical composition (such as one area has more inclusions of an iron oxide).
This could also be the result of the formation of the stone, producing a material mixed with several different kinds of materials.
It is particularly easy to see on stones that have been tumbled and/or polished.
A dark stone can have a light banding, and a light stone can have a dark banding.
Types of Banded Stones
Agate is a stone that is famous for its striking, beautiful banding.
Whatever variety of agate you find, it is sure to have bold, contrasting banding colors.
These bandings happen during the formation of agate in cavities during volcanic eruptions, where different minerals form layers over time.
Agate is primarily composed of a combination of chalcedony and quartz, and there are countless species that go under the umbrella term of agate.
They are semi-translucent stones, each with its own unique colors and banding.
Agate is sometimes used for jewelry, but most commonly used for decorative pieces, such as bookends and coasters.
Agate is an abundant stone, found all over the world.
Amethyst is known as purple quartz, which is a rather unique color for crystals and stones.
When polished, it reveals to have subtle banding of different shades of purple.
The banding on amethyst is a result of zoning, which occurs during the formation of the crystal. Like many other rocks, amethyst is created from the hot magma of volcanoes.
When the magma undergoes rapid cooling, the stone is unable to maintain chemical equilibrium, and different colors form in the crystal.
Amethyst is found all over the world, but is most bountiful in Brazil and Uruguay.
Banded Gneiss, sometimes simply referred to as ‘gneiss’, is a metamorphic rock identified by strong banding.
These bands are created by its composition of layers of varying minerals.
It is a high grade metamorphic rock where its crystalline structure has been created by high heat and pressure.
Gneiss often varies in its chemical composition, but it is most commonly made from quartz and feldspar, usually in colors of black, grey, and white.
Some species of gneiss polish well and can be used as floor tile, while others are ground up and used for construction.
It is an incredibly common type of rock, found all over the world.
Banded Iron Ore
This is a very interesting rock formation, as it consists of thin layers of iron and jasper, chalcedony, or quartz.
The iron gives it its rusty-red hue, while the other rock and mineral inclusions give it a multi-colored banding.
All specimens of banded iron ore seem to have formed from volcanic activity in Precambrian time, which is one of the earliest geologic ages.
This stone is truly ancient, and is mostly used for low-grade iron ore.
It is found mostly in North and South American, Ukraine, Australia, India, South Africa, and Russia.
Fluorite is a multi-colored translucent to transparent stone, primarily composed of calcium and fluorine.
It has banding due to color zoning, similar to amethyst.
It is primarily used for chemical purposes, glass making, high-performance telescopes, and polishes.
Some fluorite of exceptional luster is used for jewelry, but this is rare because fluorite is a very soft stone and is prone to damage.
It usually comes in yellow, purple, and green, but can be found in all colors of the rainbow.
The word ‘fluorescence’ comes from the discovery of fluorite having an exquisite illumination when light is shone through, specifically turning a bright indigo color under ultraviolet light.
It can be found in many places all over the world.
One of the most abundant stones on Earth is jasper.
It is an opaque quartz, able to accept a very shiny polish and attractive in jewelry and decorative pieces.
Since ‘jasper’ refers to a rather wide range of stones, there are many reasons why some jasper has banding.
Some acquire the banding from environmental factors, such as water and wind.
Others from mineral inclusions or natural variations in color.
Malachite has some of the most dramatic and interesting banding of any stone. It is a stunning, vibrant green with bands of darker and lighter green.
It has high levels of copper which, when exposed to oxygen for long periods of time, turn green.
The simple reason why the bands form is because of impurities.
The first deposits of malachite were found in Israel and Egypt, but have since been found in the Democratic Republic of the Congo, Russia, Australia, France, and Arizona.
Onyx & Sardonyx
Onyx and sardonyx are very close relatives to agate, all being similar species of layered chalcedony.
The difference that agate has with onyx and sardonyx is that the latter two have parallel banding, while agate has bands that are curved.
The banding on onyx and sardonyx occurs in the same way as agate, collecting different layers of minerals over time.
Onyx is typically black with white banding, although it can rarely come in other colors, as well.
Sardonyx has bands of red sard.
They are found all over the world and have been used historically for jewelry, carvings, and pottery.
Rhodochrosite is a beautiful pink stone with white banding.
Its rosy hue comes from manganese and white banding from other mineral inclusions.
It is found in very few places in the world, the most common of which is Argentina.
However, it has also been found in Peru, Romania, Spain, South Africa, Japan, and specific locations in North America.
It is rare and prized as a gemstone for jewelry.
One of the most popular gemstones in the world, tiger’s eye is famous for its holographic banding.
This banding has been dubbed ‘cat’s eye’ because of its optical light play.
It is a type of quartz and gets its beautiful banding when silica replaces crocidolite during formation.
These parallel fibers get set in the stone and produce the beautiful cat’s eye feature.
It is usually a brownish-gold color, but can also rarely be found in blues, greens, and reds, all due to unique combination of mineral inclusions.
It is primarily found in South Africa, but also can be found in Brazil, India, Burma, Western Australia, and some places in the U.S.
Banded Stones are Unique and Beautiful
There are so many wonderful banded stones to explore.
Make sure to check out the stones listed above for some inspiration.
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