Obsidian Properties, Facts and Photos

Contents 1. What is Obsidian? 2. Meaning of Obsidian 3. How Obsidian Forms 4. Obsidian Healing Properties 5. Article Pictures 6. Shop Obsidian

What is Obsidian?

Obsidian, which is volcanic glass, is one of the sharpest naturally occurring materials. When it breaks, it has a razor-sharp edge.

During the Stone Age, obsidian was used for knives, spear tips and arrows.

Obsidian breaks in the same way as window glass, with a conchoidal fracture. A conchoidal fracture is a typical characteristic of many brittle, non-crystalline solids.

A non-crystalline solid is a material that lacks an internal crystalline structure. In other words, it's not made up of crystals. These materials are correctly known as mineraloids.

Minerals, which are crystalline solids (made up of crystals), have a highly ordered (well-defined) repeating arrangement of atoms.

In a non-crystalline solid, the atoms do not come together in this way and instead are disorganised or random, with no definitive structure.


More recently, surgical scalpels have been made from obsidian instead of conventional steel. These blades create a finer incision, so wounds heal faster with less tissue damage and scarring.

Due to the metal's crystalline structure, a steel scalpel's cutting edge is similar to a saw. The edge of a non-crystalline material is smooth, so the incision is cleaner and more precise.

The problem with using obsidian for this purpose is that it's not particularly hard and is also brittle.   

Different types of obsidian can be found in many locations around the world. Oregon has many gem-grade varieties, including mahogany, red, black, rainbow and snowflake obsidian.

The colour of obsidian is determined by inclusions and/or impurities present. Tiny bubbles caused by water vapour, air or gas can also produce different types of sheen.

Material with a golden sheen is known as sheen obsidian, while obsidian with circular-like patterns that's iridescent is known as rainbow obsidian.

Hematite causes the red and brown varieties, whilst inclusions known as spherulites (spherical bodies) cause the whitish-grey markings in snowflake obsidian.

Iron and magnesium produce black obsidian, which is the most well-known variety.

The spherulites in snowflake obsidian are difficult to see in detail without powerful magnification. They're known to have radiating fibrous needle-like crystals composed of christobalite and feldspar.

The word 'vitreous' is widely used to describe a rock, mineral, or gemstone whose surface interacts with light in a way similar to glass. While obsidian has a vitreous lustre, spherulites often have a duller lustre than the host rock.

On the Mohs scale of hardness, obsidian grades 5 to 5.5. Being natural glass, it's brittle, so must be handled carefully. Most obsidian comes from countries with extensive volcanic activity.

Polished black obsidian was used as a mirror by the Aztecs and Greeks. It was widely traded by many ancient cultures primarily because of its sharp edges, which made it ideal for blades and tools.

Obsidian continued to be used in the ancient Middle East for thousands of years after the introduction of metals. 

Meaning of Obsidian

The meaning of the word 'obsidian' (Latin: obsidiānus) is said to have come from a misreading involving the word 'obsiānus'.

'Obsiānus lapis', meaning Obsius's stone, refers to a stone found by Obsius. 'Lapis' is Latin for 'stone'.

Pliny the Elder Roman author, naturalist and philosopher [23 AD - 79 AD], wrote in his works Naturalis Historia in reference to obsian glass and obsian stone:

Among the various kinds of glass, we may also reckon Obsian glass, a substance very similar to the stone which Obsius discovered in Ethiopia.  The stone is of a very dark colour, and sometimes transparent; but it is dull to the sight, and reflects when attached as a mirror to walls, the shadow of the object rather than the image.  Many persons use it.   (Naturalis Historia chapter 67) (Note).

How Obsidian Forms

Obsidian forms when a specific type of magma cools and solidifies. The magma often cools so rapidly that crystals do not have time to grow. 

Magma is molten rock from beneath the Earth's surface. Once expelled from the vent of a volcano, it becomes known as lava.

Lava initially cools quite fast, but the process slows down due to its insulating properties.

If lava cools very fast, as in hours to days, crystals have insufficient time to grow. They may form after a few weeks but will only be sub-micron.

There are many different types of volcanic glass. The type that forms depends on the nature of the volcanic eruption, the chemical composition of the magma, the presence of gases, and the speed at which the lava cools. The magma that forms obsidian typically has low gas and water content.

Other varieties of volcanic glass include pumice, apache tears, perlite and pitchstone, but there are many more. Perlite is a hydrated volcanic glass that expands when heated. Apache tears are small, tear-shaped or rounded nodules of obsidian.

Some of the finest obsidian forms beneath the surface of the Earth as magma seeps between fractures in rocks. This tends to occur close to the volcano's vent. The natural glass that subsequently forms is often free from dirt, ash and other impurities. 

Most magma contains at least 70% silicon dioxide which is the main constituent of obsidian.

Although obsidian is often called a stone, some geologists argue that it's not an accurate description. The problem, however, is coming up with something more suitable. One respected geologist describes obsidian as 'a congealed liquid with impurities of rock and a limited number of microscopic crystals.'

Obsidian Healing Properties

Obsidian cuts to the heart of the matter. It brings issues to the surface and can be very confrontational to the user. Those who use obsidian for its healing properties should be prepared for a full onslaught.

During the Middle Ages, obsidian was used to drive out evil spirits and demons. Today, it can be used to clear unwanted energies from the aura or from within the home.

Obsidian acts like a shield repelling negative or harmful energy. It can help you deal with difficult situations clearly and directly. It works hard to resolve issues so you can move on and start afresh.

Obsidian encourages open and honest dialogue regarding family matters and can improve communication by allowing thoughts, feelings, and concerns to be expressed respectfully and constructively.  

Black obsidian supports and comforts those who are grieving or temporarily separated from a loved one. It can also be used to sever unwanted ties or to distance yourself from those who drain your energy.

Sleeping with black obsidian deepens sleep and enhances the experience of astral journeys.

Meditating with or carrying obsidian helps you remain centred and grounded. It connects with Earth's energies to promote balance, clarity and focus.

Obsidian enhances intuition, psychic ability, and spiritual growth, and provides a clear channel for receiving insights and messages from higher realms.

Article Pictures

The first picture in our article is obsidian with a conchoidal fracture. The last photo is of green obsidian from Oregon. Both photos are courtesy of Stan Celestian. 

The snowflake obsidian is courtesy of James St.John. All three photos are clickable and redirect to the original image.

The red obsidian was once part of our collection.

Pop-up photos: Botryoidal Hematite - Courtesy of Ron Wolf. Pumice, apache tear, pearlite  - Courtesy of Stan Celestian.