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Volcanoes spit out molten rock from deep inside the earth, which then hardens into “new” rocks.
“Old” is relative. Rocks 50 million years old are considered very young geologically, some parts of the crust hardened four billion years ago.
Now if you’re asking how old the magma innards of the Earth are, that’s a more complicated question with a few different answers.
>Now if you’re asking how old the magma innards of the Earth are, that’s a more complicated question with a few different answers.
In general, the mantle is solid save for a few melty patches right near the top, eg. directly underneath mid-ocean ridges. If you were to pick a random spot on Earth’s surface away from such places though, it would be around 2,900 km of solid rock below your feet before you reached the core. The outer core is indeed molten, though technically not magma, as it is molten metal rather than silicates/rock.
The Earth’s insides separated into mantle and core as it was still accreting (you only need to be about as big as [Ceres](https://en.wikipedia.org/wiki/Ceres_(dwarf_planet)) before this starts to happen), it’s thought that differentiation was complete within 20-100 million years of Earth’s formation as a planet (depending on which research group you go by). So about 4.4 billion years old is an age for the core and mantle having existed, though it’s likely that the mantle was a little different to start with. The eons of plate tectonic processes have chemically evolved the mantle by producing continental crust.
There are a lot of new stone on Iceland now. Im not sure if the vulcano has stopped so that it is safe to pick it up but its there.
Magma/lava are made of molten rock, when it cools down it becomes regular rock.
Yes, rocks are constantly forming, albeit at a very slow pace.
As sediment falls to the bottom of oceans, layers build up and eventually the pressure and temperature gets big enough to chemically produce large minerals. We call them rock.
You also have volcanoes constantly spewing magma from the core of the earth. When this lava cools, it forms igneous rock layers.
It depends on what you mean by "new". Rocks are formed all the time, but are recycled from other rocks. See: volcanos. When a volcano erupts lava flows out, cools, and becomes one of a variety of rocks depending on how it cooled and what kind of lava it is. We can actually track the flipping of the earths geomagnetic poles this way by looking at the magnetic alignment of iron bearing rocks on the floor of the Atlantic.
Sedimentary rocks take a lot longer to form but are made from sediment laying down over time. When it becomes a rock rather than sediment is kind of a gradient.
And then metamorphic rocks are rocks that turned into other rocks. Are they new? This has a similar time judgement issue as sedimentary though, they gradually turn from one to another.
Rocks of any type can have been made relatively recently. Go to a volcano with a fresh lava flow you can watch it cool into rock.
We can also make some stones ourselves, like diamonds by chemical vapor deposition or halite by evaporating salty water. All of those would be quite young.
Depends what you mean by “a stone”. The ingredients of the world are mostly all the same age. Dust and debris falls in from space every day, but really slowly. There are new pebbles made from old minerals, new quartz made from old sand, and so on. If you think mineral salts and sand are “stone”, then nothing’s new.
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Volcanoes spit out molten rock from deep inside the earth, which then hardens into “new” rocks. “Old” is relative. Rocks 50 million years old are considered very young geologically, some parts of the crust hardened four billion years ago. Now if you’re asking how old the magma innards of the Earth are, that’s a more complicated question with a few different answers.
>Now if you’re asking how old the magma innards of the Earth are, that’s a more complicated question with a few different answers. In general, the mantle is solid save for a few melty patches right near the top, eg. directly underneath mid-ocean ridges. If you were to pick a random spot on Earth’s surface away from such places though, it would be around 2,900 km of solid rock below your feet before you reached the core. The outer core is indeed molten, though technically not magma, as it is molten metal rather than silicates/rock. The Earth’s insides separated into mantle and core as it was still accreting (you only need to be about as big as [Ceres](https://en.wikipedia.org/wiki/Ceres_(dwarf_planet)) before this starts to happen), it’s thought that differentiation was complete within 20-100 million years of Earth’s formation as a planet (depending on which research group you go by). So about 4.4 billion years old is an age for the core and mantle having existed, though it’s likely that the mantle was a little different to start with. The eons of plate tectonic processes have chemically evolved the mantle by producing continental crust.
There are a lot of new stone on Iceland now. Im not sure if the vulcano has stopped so that it is safe to pick it up but its there. Magma/lava are made of molten rock, when it cools down it becomes regular rock.
Yes, rocks are constantly forming, albeit at a very slow pace. As sediment falls to the bottom of oceans, layers build up and eventually the pressure and temperature gets big enough to chemically produce large minerals. We call them rock. You also have volcanoes constantly spewing magma from the core of the earth. When this lava cools, it forms igneous rock layers.
It depends on what you mean by "new". Rocks are formed all the time, but are recycled from other rocks. See: volcanos. When a volcano erupts lava flows out, cools, and becomes one of a variety of rocks depending on how it cooled and what kind of lava it is. We can actually track the flipping of the earths geomagnetic poles this way by looking at the magnetic alignment of iron bearing rocks on the floor of the Atlantic. Sedimentary rocks take a lot longer to form but are made from sediment laying down over time. When it becomes a rock rather than sediment is kind of a gradient. And then metamorphic rocks are rocks that turned into other rocks. Are they new? This has a similar time judgement issue as sedimentary though, they gradually turn from one to another.
Rocks of any type can have been made relatively recently. Go to a volcano with a fresh lava flow you can watch it cool into rock. We can also make some stones ourselves, like diamonds by chemical vapor deposition or halite by evaporating salty water. All of those would be quite young.
I have a piece of one of the newest rocks in California and it is barely 100 years old. Still very young. So no, not all are old.
Depends what you mean by “a stone”. The ingredients of the world are mostly all the same age. Dust and debris falls in from space every day, but really slowly. There are new pebbles made from old minerals, new quartz made from old sand, and so on. If you think mineral salts and sand are “stone”, then nothing’s new.