Yellowstone's Obsidian Cliff: its amazing geologic story 

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Obsidian tend to develops inland volcanos. After all need rich silica’s low water.

remember you can’t take anything from the park - it’s illegal but it must of been cool back before the colonizers showed up to find a stash of obsidian to make tools and arrows with ! awesome thanks!

It sure can be sharp, and its "cousin", rhyolite, also can have very sharp edges. I have gotten some nasty cuts opening boxes of both rocks that I'd ordered for tumbling so I have learned to be very careful when handling this material. I have also had rhyolite cut all the way through the rubber barrels of a rock tumbler during the first phase of tumbling. It is easy to see why this material was so sought after by ancient cultures the world over for making projectile points and tools.

Yes, The NPS has zero tolerance regarding collecting or even the possession ( even in your car) of prospecting equipment, such as a rock hammer, gold pan, or gem screen. If you are passing through the park system, be sure any equipment is stowed out of sight.

yeah, even though they could mine it and sell it to sucker...err, tourists and never run out

@@ThatOpalGuy Sure, mines are endless sources of minerals ... The country is full of obsidian localities were you are allowed to collect. The Mining Law of 1872 was written the same year National Parks were created. Your childish disregard for law is disturbing and not representative a Christian.

@@wiregold8930 Why bring religion into it? I see plenty of so called christian with a disregard for law & decency, who also lie, cheat and steal. I also people who aren't christians, who do the same. So I ask again, why bring religion into it?

Come on out to Oregon and visit Glass Buttes. You can pick up and surface mine 50 pounds… per visit. The obsidian is top quality.

I think that’s common knowledge except to a few dunderheads who don’t obey signs at the park. They are the ones dancing with bison.

@@drhyshek It's because of them the reminder is necessary.

One could add, 'don't even bring your rock hammer or gold pan in the car' as they are considered prospecting equipment which is forbidden.

thats for sheep, not PAYTREEUTS

@@wiregold8930 sorta makes it hard if youre a prospector and just passing through.

obsidian can be found in many places all over the country not just this cliff

Thanks for watching and learning with me. More Yellowstone (and other) videos coming soon.

The lava flow in the northeast park has petrified trees

If it isn't already on your list, go visit Glass Butte in Oregon. It's basically a small mountain of various colors of obsidian...and you're allowed to collect.

agreed, autofocus can be a bane or a boon, it just depends on the day

Hi Mark. Yes, I do field trips for RU-vid viewers throughout the year. In Oct, I ran two one day trips around Twin Falls. I’ll do some more this year in April and June. Look for announcements and sign ups soon. I also have a trip to Iceland in May for folks.

Awesome! I will definitely be watching for signups. However, I don't think Iceland is in the budget. 😅 thanks and keep up the great videos!

chemically its granite.. when he was pointing out that it was without minerals... there's still minerals in there just none of them have crystallized. but obsidian is chemically granite or rhyolite rhyolite is also granite I've got my own theories about that stuff but I'm not telling you anything that I'm not certain of

oh the first part of your question yes that would be felsic magma like a Mount St Helens it's very sticky so it doesn't flow which is why I have my own theories on its formation but I'll leave that for my channel at some point

Dave's reply here is good but I'll add a bit more. Obsidian forms when "dry" (low water content) felsic (meaning rich in silica) magma cools quickly at the surface. Mafic magmas like basalt do not make obsidian even when they flow into water or erupt beneath ice. Intermediate magmas like andesite would not form obsidian either. So, obsidian forms when you have the right magma type (dry and silica rich) cooling quickly at the surface. The elements are unordered and haven't combined to make minerals so it creates a glassy texture. Glass is unstable, and technically a very viscous liquid, so it slowly devitrifies ("deglassifies") over time. The elements in the obsidian move very slowly, bond with other elements, and make crystals over time as elements move slowly and build crystals. These are the rounded spherulites seen in the video. Hence, the obsidian will slowly turn into a crystalline rock like rhyolite. Therefore, all obsidian is very young geologically (usually less than 15-20 million years at most). Hope this helps a bit.

@@shawnwillsey That makes sense, thanks!

@@shawnwillsey Thanks for an informative answer about this theme which I find very interesting. I was here ( on the road next to it ) 5 years ago, but unfortunately there were road works going on here, so I couldn't get to this outcrop. I did see some south of Madison, but it looked quite different than this. One question I really wonder about is when obsidian have crystalized after some tens of millions of years, is it then possible to see from the new rock type - presumably rhyolite - that it previously was obsidian ? What features of the new rock type would reveal it to previously have been obsidian? I suspect some areas where I live originally were obsidian. They are several hundred million years old.

The pumpkin obsidian has the reddish color due to some of the iron being oxidized. I don't think it is due to increased water content.

Hi Chuck. See my detailed reply to "No Thanks" below. Age is 105,000 years old.

glass lasts a long time. but geologically i guess it does weather as fast, or faster, than rock

Welcome aboard and enjoy the existing videos in the collection.

never mind that it would take thousands of years for that to happen. the actual danger are the capitalists

@@ThatOpalGuy Like communists never used steel with forced labor. There's always one that has to bring politics into everything and it's always the one that does the least.

There is another obsidian cliff in the park some distance from any road and it is kept secret as there are deep pits dug by natives extracting obsidian. This obsidian was considered the finest of all and traded as far as 1000 km away.

all this time they were breaking the white mans law

we have tons of these columns in the boise area, on the way to Lucky Peak. climbers love to climb them

in other words, you can only collect obsidian in hell

Uh yeah, shredding your hands is counterproductive. I'm sure it would hold a cam or nut though.

Yes. Obsidian is technically an amorphous solid.

@@shawnwillsey thank you! nice to see some definitions stay the same,, rock solid ? lol cheers!

I think not. Here is what Big Wild Adventures says about poison Ivy in Yellowstone. Bear in mind that the elevation of the Obsidian Cliffs is 7,400 feet. ". . . “rare” is not the same as “absent”! Poison ivy is a deciduous shrub with a skin-irritating oil with which most folks are familiar. It grows in temperate climates with adequate moisture, which excludes much of the arid and high altitude West. Since most of the Yellowstone and Tetons region is above 7,000 feet, and those areas that are lower are mostly semi-arid, this region is not conducive to robust populations of poison ivy . . . ."

Probably rhyolite. Basically the same material but where minerals nucleated.

Hey that's a solid question so thanks. Obsidian lacks mineral crystals and so it breaks along curved surfaces called conchoidal fracture. This is also how man-made glass (also lacking crystals) breaks. The larger fractures forming the columns in Obsidian Cliff are related to how this silica-rich lava cooled. The top (in contact with the air) and bottom (in contact with the ground) cooled quickly, causing the lava to contract and form fractures which propagated through lava and linked to form continuous fractures.

That would deprive future visitors the chance to discover and view "a nice piece". Most rockhounds I know have more respect for the material than you have displayed.

Yes, I've read chemical signatures identified Yellowstone obsidian in Illinois. There is another obsidian cliff with deep pits dug by natives but the park service keeps that location a secret.

There is an interesting book on the topic of the Native American presence in the area that became Yellowstone NP. “Before Yellowstone” by Douglas H. MacDonald from the University of Washington Press. (2018) The book mentions how X-ray fluorescence can be used to determine the amount of silica in the obsidian and consequently determine a signature for obsidian from different locations. So a found obsidian tool can be traced to its origin!

There is another larger obsidian cliff in the park which is kept secret. It's not near any roads.

It's inside a National Park, and the rangers take their job very seriously. Attempt to take some chips home and you'll be facing legal troubles of a Federal nature.

Do you know how crazy your statement is? There is literally a mountain of obsidian at Obsidian Cliff, and that's just at that one site! There are many places to find obsidian in the western states and Mexico. Also, Obsidian Cliff is inside Yellowstone National Park! Get it, its a National Park! It was made a national park by Theodore Roosevelt, it belongs to the citizens of the US and for all to enjoy (for a small fee)! It's also shown on the maps the Park Service hands out to all vehicles as they enter the park!

Try dismantling a cliff in a National Park.

…even when lava flows-out under water, even at depths around spreading centers where the water temperature is barely above freezing, where it forms “pillow “ lava there is only the thinnest of obsidian rimes over what quickly cools into pillow basalt, not pillow obsidian. Even in In arctic regions where temperatures are much colder, still, than at the bottom of the ocean, lava cools into basalt not obsidian. There has to be another process involved other than rapid cooling. What is this process?