All About Obsidian – Uses, Properties, Color, and Worth

Obsidian is an igneous rock that is formed from the erupted lava of a volcano.  Obsidian is made of felsic type material, rich in feldspar and quartz, which is high in silicate minerals. This formed rock is considered to be one of natures occurrences of natural glass.

Obsidian is an extrusive igneous rock and not an intrusive rock. Being extrusive means obsidian cooled quickly at or near the surface of the earth.  The high content of thick silica, along with rapid cooling, forms obsidians natural glassy texture as there is little time for crystallization.

Some give question as to why obsidian is not a mineral. Obsidian is not a mineral because firstly, it does not have any crystal form but instead is glass. Secondly, obsidian has too irregular of a composition. Many will call obsidian a mineraloid, or being similar to a mineral but not a mineral.

Obsidian is unique and there are really no obsidian types of rocks that equal it. Obsidian has a hardness of 5 to 6 on the Mohs scale of hardness.  Although being a relatively hard type of rock, it is quite brittle and can fracture into sharp edged pieces.   

Additionally, this rock can be found quite commonly in roundish forms often called Apache tears. This is due to years of erosion from earthly elements as the rocks will roll down hills and rivers.

What is Obsidian used for?

Obsidian is used as decoration and jewelry.  The igneous rock can be cut into shapes and used in earrings, necklaces, bracelets, and pendants.  When obsidian is used for decoration it can take many shapes such as carved out figurines, bookends, and just cut out into cabochons for display.

The use of obsidian has some history. Native Americans found that obsidians ability to chip off into sharp edges was quite useful.  Spear heads, arrow heads, and many other tools were carved out from the rock to help in uses of day to day survival.  With the potential sharpness of obsidian, many still today like to carve out knives, axes, and other objects with the rock.

The trade of obsidian among the natives in America was fairly common.  With all the uses of obsidian, including the use of jewelry, the trade of obsidian could be thought of as one of the first businesses in America.  It has been historically documented that some obsidian was traded to very distant tribes. It has be found that obsidian from one location had travelled over thousands of miles to end up at another location.

The Colors of Obsidian

Obsidian color is black, brown, lighter browns, and green.  In some rare cases obsidian can have the color of red, orange, yellow or even blue.  Black and gray is the most common type of color for this rock.

There are various types of obsidian rock that people have coined names for based on their colors and appearance. Some of these types of obsidian are:

• Snowflake Obsidian – Contains white looking snowflakes.
• Sheen Obsidian – Shows reflective colors such as, gold, silver, green, and purple.
• Fireworks Obsidian – Contains white or red looking firework explosions.
• Mahogany Obsidian – Has reddish and brownish inclusions.
• Spider Web Obsidian – Contains long white strands like spider webs.
• Peacock Obsidian – Has a velvet look with pinks, purples, and greens.

People wonder why obsidian is commonly the color black. A majority of obsidian is black due to extremely tiny inclusions of iron oxide and the mineral magnetite contained within its glassy structure. Other minerals in obsidian such as hornblende, plagioclase, biotite, and pyroxene can be present as well supporting a darker look.

The more rare colors can include minerals such as hematite, limonite, and small crystals of various feldspars.

Snowflake obsidian is black obsidian that has white, uneven blooming, dots within the rock.  These white inclusions give the appearance of a snowflake at times hence the snowflake designation.  The mineral cristobalite is what gives the white snowflake look on snowflake obsidian.

Rainbow obsidian is a sheen obsidian that has some specific planes internally to the rock when it was formed from its original lava.  In this case the light will reflect in a way that allows the color of green, violet, or silver to be seen.

The Worth of Obsidian

Obsidian worth is not very much and has a price of around $1 to $2 per pound.  This mineral is not rare and can be found in abundance all over the world.  The worth of obsidian will increase for specimens with a rare color, different appearance, and size.  

The value of obsidian will increase with larger pieces of obsidian that are cut into objects such as crystals or figurines. In these cut out shapes they can fetch hundreds of dollars. The larger the carved object, the more you might expect to pay.  Larger uncut, or loose pieces can typically be purchased at per pound prices.    

It is very common for people to be able to get cut obsidian for under a hundred USD.  Hand sized balls, small carvings, and some jewelry can end up being very affordable.  Keep in mind though, you will pay more, a lot more in some cases, for some of the different types of obsidian as mentioned above.

Is Obsidian Harder Than a Diamond?

Many may come to believe that obsidian may be stronger than a diamond. These notions may come from sources such as media type venues such as games that have obsidian as an item used in its gameplay.

Obsidian is not harder than a diamond. Obsidian has a hardness on the Mohs scale of hardness of roughly around a 5 or a 6. A diamond has a hardness of a 10 on that same scale, being the very definition of 10.

Obsidian however can be sharper than a diamond. Obsidian, due to its nature when it breaks, can be many times sharper than a typical razor blade.

Obsidian Texture

Obsidian texture is very smooth. This rock is referred to as one of nature’s forms of natural glass. Obsidian can be found with a rough look after being exposure to the earth’s surface. However, when it breaks, its texture will be as smooth as glass.

Obsidian Look Alikes

There are some obsidian look alikes such as onyx, jet, and tourmaline which are confused primarily based color and appearance. These look alikes do have some differences which set them apart from obsidian despite them looking similar.

The differences in black obsidian vs black tourmaline are primarily that obsidian is a igneous rock while tourmaline is a mineral. Both minerals can be black, but both can display other colors in a very different way. Tourmaline is harder on the Mohs scale of hardness at a 7 to 7.5 however this mineral could never get as sharp of an edge as obsidian.

The differences in obsidian vs onyx are mainly onyx is considered a mineral where obsidian is not. Onyx is much like agate, as it is a oxide mineral with a chemical formula of SiO₂ where obsidian contains SiO₂ with iron and magnesium. Onyx is considered a fairly valuable gemstone and fetches higher prices than obsidian.

Finding Obsidian

Obsidian will be found in and around rhyolitic eruptions as its own flow called an obsidian flow. If you are in an area and can recognize rhyolite, you may also be lucky find obsidian. In some cases obsidian can travel long distances away from any original lava flows by rivers and other forces of nature.

There are several commonly known places where Obsidian will be found around the world; Hungary, Italy, Japan, Mexico and in the USA the states of Arizona, California, Idaho, Oregon, and Utah.