Obsidian Glass



Obsidian is a massive volcanic glass. The term ‘massive’ has several (although related) meanings in geology but here it means that the rock (obsidian is a rock type, not a mineral) is homogenous. It lacks layering, cleavage, foliation, phenocrysts, etc. It is just a piece of volcanic glass without further conditions. In the majority of cases obsidian solidified subaerially (on land). Volcanic glass that formed underwater has alternative names like tachylite and hyaloclastite.

One way we like to get Obsidian Glass is by breaking into fortresses. By finding and clearing out forts in Assassin’s Creed: Odyssey, you can earn a plentiful amount of valuable loot, including Obsidian Glass. Additionally, you can break down items you already own and no longer want to add more Obsidian Glass to your inventory. OBSIDIAN ROUGH DAMASCUS OBSIDIAN ROUGH VOLCANIC GLASS BANDED OBSIDIAN 2LB 5OZ. $11.80 shipping. Mahogany Obsidian Free Form Oregon 40 grams Lapidary Rough Display. Ending Apr 9 at 6:47PM PDT 6d 18h. CSS: 1.7 lb Piece Of Glass Buttes Rainbow Obsidian Rough Knapping Oregon.


Typical obsidian is either black or slightly reddish and often demonstrates beautiful conchoidal fracture. Width of sample 11 cm.

Glass

So the volcanic glass and obsidian are not synonyms although in many cases you can freely use both terms. It is definitely not wrong to use ‘volcanic glass’ instead of ‘obsidian’ but you should be careful the other way around — volcanic glass is not always obsidian.

  • One way we like to get Obsidian Glass is by breaking into fortresses. By finding and clearing out forts in Assassin’s Creed: Odyssey, you can earn a plentiful amount of valuable loot, including Obsidian Glass. Additionally, you can break down items you already own and no longer want to add more Obsidian Glass to your inventory.
  • The main way I use tags is to make searching for notes with a specific attribute. In the example shown in the screenshot above, I click on the search option (the magnifying glass shown in the image above) and type in my tag including the # sign in the search box. Obsidian will display all the results that contain that tag.
  • Snowflake Obsidian Glass Volcanic Rock - 2 Raw Pieces. 3.7 out of 5 stars 4. Only 9 left in stock - order soon. ELITE Square Volcanic Pattern Tempered Glass Bathroom Vessel Sink & Oil Rubbed Bronze Finish Faucet Combo.

Volcanic glass is an igneous rock that is composed of largely uncrystallized magmatic material. Most of it is not crystallized because the crystals had two difficult problems which restricted their growth. The first one is time. Large crystals need a lot of time to grow. There is very little of it when viscous magma is pushed out of a volcano and cools rapidly. I already gave a subtle hint what the second problem might be. It is the viscosity of magma/lava. If the magmatic body is very thick or viscous, the crystals have a really hard time forming because they simply don’t have new material coming in if almost nothing is able to move inside the magma body. The result is that everything solidifies just randomly as glass.

So obsidian forms from viscous magma only? Usually yes, but not always. Most obsidians are rhyolitic in composition. This lava is the thickest because it has the highest silica content. Why is that important? Because silica causes magma to polymerize. There are countless bridges (chemical bonds) between oxygen anions of silica (SiO2) which is the reason why this magma is so hard to move. If the magma contains lots of metals (cations) then it is less viscous because these cations break the framework structure of silica. I think this point is important and worth paying attention to because lots of people seem to think that rhyolitic magma is more viscous than basaltic magma only because its temperature is usually lower.


Vesicular basaltic volcanic glass from Punalu’u Beach, Hawaii. Width of view 20 mm.
Obsidian with gray layers of rhyolitic pumice in Long Valley Caldera in California. Pumice and rhyolite have very similar composition but they differ in texture — pumice is highly vesicular while obsidian is massive.

Is some volcanic glass still basaltic in composition? Yes, but in this case the cooling has been really rapid. This is the case if basaltic lava is flowing into the water. There are some nice black sand beaches in Hawai’i that are composed of fragments of volcanic glass with basaltic composition.

How to identify small obsidian fragments like sand grains? In most cases it is not too hard to do by optical examination only. Obsidian is usually black although reddish varieties are pretty common also. Obsidian has a strong luster and conchoidal fracture. This means that fracture surface is smoothly curving (like a seashell).

Obsidian is usually black. This color is caused by minute inclusions and tiny crystals in the glass. Red color is caused by the same stuff that gives red color to weathered basalt, desert sand and K-feldspar. It is mineral hematite (iron oxide).


Obsidian is usually dark and its surface is shiny.

Obsidian is not stable in the weathering environment but it does not mean that it can not last millions of years. Obsidian on the Moon may be billions of years old because the Moon is dry. The same applies here on the Earth as well. In dry areas obsidian can last pretty long. However, obsidian formations older than the Cenozoic (it began 65 million years ago) are unknown.

Here are two pictures of obsidian grains picked from coarse-grained sand samples.


Obsidian from the Yellowstone National Park. Width of view 35 mm.


Obsidian from NE California (The Cascades volcanic range). Width of view 22 mm.

People had used naturally occurring glass, especially obsidian (the volcanic glass) before they learned how to make glass. Obsidian was used for production of knives, arrowheads, jewelry and money.

The ancient Roman historian Pliny suggested that Phoenician merchants had made the first glass in the region of Syria around 5000BC. But according to the archaeological evidence, the first man made glass was in Eastern Mesopotamia and Egypt around 3500BC and the first glass vessels were made about 1500BC in Egypt and Mesopotamia. For the next 300 years, the glass industry was increased rapidly and then declined. In Mesopotamia it was revived in the 700BC and in Egypt in the 500’s BC. For the next 500 years, Egypt, Syria and the other countries along the eastern coast of the Mediterranean Sea were centers for glass manufacturing.

Obsidian glass paint

Sherwin Williams Obsidian Glass

In the beginning it was very hard and slow to manufacture glass. Glass melting furnaces were small and the heat they produced was hardly enough to melt glass. But in the 1st century BC, Syrian craftsmen invented the blow pipe. This revolutionary discovery made glass production easier, faster and cheaper. Glass production flourished in the Roman Empire and spread from Italy to all countries under its rule. In 1000 AD the Egyptian city of Alexandria was the most important center of glass manufacture. Throughout Europe the miraculous art of making stained glass on churches and cathedrals across the continent reached its height in the finest Chatres and Conterbury cathedral windows produced in the 13th and 14th centuries.

Glass History

The very first glass known to stone age people which was used for making weapons and decortaive objects, was obsidian, black volcanic glass. The earliest known man made glass are date back to around 3500BC, with finds in Egypt and Eastern Mesopotamia. Discovery of glassblowing around 1st century BC was a major breakthrough in glass making.

Glass Invention

Glass was first made in the ancient world, but little is known about man’s first efforts to make glass. Amulets and solid beads were made in Mesopotamia as far back as 2500BC. Later, glass making was further developed in Egypt around 1500BC.

Glass Making

Did you ever wonder how glass is made? What are ingredients of glass? How many types of glass are there? Here you can read about glass making process and related information.

Glass Manufacturing History

By the time of Crusades, glass manufacturing was developed in Venice and it became glassmaking center of the western world. In 1291 glassmaking equipment was transferred to the island of Murano. During 15th century Venetian glass blower, Angelo Barovier, crated cristallo, nearly colorless, transparent glass. By the late 1500’s, many Venetians went to northern Europe seeking better life where they established factories and brought the art of Venetian glassblowing.

By 1575, English glassmakers were made glass in Venetian fashion. In 1674, an English glassmaker George Ravenscroft invented lead glass.

The first glass factory in the United States was built in Jamestown, Virginia in 1608.

In the early 1800’s, there was a great demand for window glass which was called crown glass. In the 1820s, the age of blowing individual bottles, glasses and flasks was ended by the invention of a hand-operated machine. In the 1870s, the first semi-automatic bottle machine was introduced.

Obsidian Glass Valheim

After 1890, glass use, development and manufacture began to increase rapidly. Machinery has been developed for precise, continuous manufacture of a host of products. In 1902, Irving W. Colburn invented the sheet glass drawing machine which made possible the mass production of window glass. In 1904, the American engineer Michael Owens patented automatic bottle blowing machine.

Obsidian Glass Knife

In 1959 new revolutionary float glass production was introduced by Sir Alastair Pilkington by which 90% of flat glass is still manufactured today.

Fire Obsidian Glass Butte Oregon

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