Any information on this rock

[VitaAmare]

This rock has been in my backyard for years, but the other day I finally took a closer look at it. If anyone could give me any additional information on it, it would be greatly appreciated. It does appear to have some quartz in white and I think I saw some pink. Also there is something green in it as well. In the pictures the rock is wet as I tried to wash all the dirt off of it. I have a few others once I noticed that I think could be something too, so I just need to clean them up. I like near what was once an active volcano (Mount St. Helena), as well as the Pine Flat area in Sonoma County which was one a mining area.

 

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[rock]

How big is it? What state did it come from? Was it found by the ocean? It looks almost like coral that I have seen in Florida. I like it.
Welcome to the site, rock

 

[VitaAmare]

It weights over 24 pounds and is about 16 inches long, 5 inches tall, and 8 inches wide. Although those are not exact measurements. It came from Northern California I believe in the mountains where there were a bunch of mines as well as in the vicinity of what was once an active volcano.

 

[Turkısh Man]

Metamorphic rock
Metamorphic rock is the result of the transformation of an existing rock type, the protolith, in a process called metamorphism, which means "change in form". The protolith is subjected to heat and pressure (temperatures greater than 150 to 200 °C and pressures of 1500 bars[1]) causing profound physical and/or chemical change. The protolith may be sedimentary rock, igneous rock or another older metamorphic rock. Metamorphic rocks make up a large part of the Earth's crust and are classified by texture and by chemical and mineral assemblage (metamorphic faces). They may be formed simply by being deep beneath the Earth's surface, subjected to high temperatures and the great pressure of the rock layers above it. They can form from tectonic processes such as continental collisions, which cause horizontal pressure, friction and distortion. They are also formed when rock is heated up by the intrusion of hot molten rock called magma from the Earth's interior.
The study of metamorphic rocks (now exposed at the Earth's surface following erosion and uplift) provides us with very valuable information about the temperatures and pressures that occur at great depths within the Earth's crust.
Some examples of metamorphic rocks are gneiss, slate, marble, schist, and quartzite.

A good example of the metamorphosis process




Orthoquartzite is very pure quartz sandstone composed of usually well rounded quartz grains cemented by silica. Orthoquartzite is often 99% SiO2 with only very minor amounts of iron oxide and trace resistant minerals such as zircon, rutile and magnetite. Although few fossils are normally present, the original texture and sedimentary structures are preserved. The term is often misused, and should be used for only tightly-cemented metamorphic quartzites, not quartz-cemented quartz arenites[3]. The typical distinction between the two (since each is a gradation into the other) is a proper quartzite is so highly cemented, diagentically altered, and metamorphosed that it will fracture and break across grain boundaries, not around them.
Quartzite is very resistant to chemical weathering and often forms ridges and resistant hilltops. The nearly pure silica content of the rock provides little to form soil from and therefore the quartzite ridges are often bare or covered only with a very thin soil and little vegetation.

 

[rock]

It weights over 24 pounds and is about 16 inches long, 5 inches tall, and 8 inches wide. Although those are not exact measurements. It came from Northern California I believe in the mountains where there were a bunch of mines as well as in the vicinity of what was once an active volcano.

Do you have any smaller ones? And what is the texture on it? Is it smooth or grainy.

 

[VitaAmare]

No this is the only one like this, and it's texture is both smooth and a little grainy depending on which part of the rock you are looking at. It is the only one like it that I have. There are other interesting looking rocks I have as well, but I have not cleaned them up yet. I believe my Grandpa or Great Grandpa took them from the hunting cabin we had near one old mines. Once I clean up the other rocks a little I will post them as well. Some do appear to be some sort of quartz, a couple I have no idea. And I have some large pieces of lava rock. One if probably 20+ pounds as well.

Thank you both Rock and Turkish Man for your replies.

 

[rock]

When you say lava rock, what color is it and is it shinny?

 

[VitaAmare]

I've attached some pictures to the lava rocks.

 

[rock]

Yeah that one is quite grainy

 

[StoneWhisper]

I love the design the quartz made through out the rock in the first few images.. clearly when someone asks, "how do rocks form?" images like those above should always be used as some sort of reffeance. most never realize that rocks/stones etc.. alwasy start out in a liqued state then harden over time. Clear evedince of this in the images above.. thanks for sharing.

 

[VitaAmare]

I have walked by that rock for years and never really thought to look twice at it until the other day. It really is an interesting rock. Once I get more information about it I will probably put it up for sale. I'm not sure if they allow it on this website. But I know there is someone out there who would really love to have it and it wouldn't just be sitting in my side yard. I'm sure if it was cleaned properly it would be even more beautiful that it is.

 

[VitaAmare]

I know it doesn't show up the best in pictures because my camera phone doesn't take the best close ups, but there is some sort of green mineral or gemstone in it that really has me curious. I attached a picture of it as well.

 

[rock]

Yeah doesnt show. I know people on this site that make modern arrowheads. That is why I was asking about the texture of your rocks. I find flint here but the exotic stones are hard to find. That one is probably too hard of a stone. And in order to sell you have to be a charter member (like me). Although I do have listings on arrowheads in the treasure classifieds page I have yet to sell a single thing. Not even a show of interest and the prices are very low compared to retail. Good Luck, rock

 

[VitaAmare]

I do have some obsidian as well. They are smaller rocks, about 1-3 pounds a piece. I think I have 5 of them. One does look like it was used as a tool at one point, possibly be Indians in the area. I can upload pictures if you like.

 

[Eu_citzen]

Commonly called "druzy quartz". Still got it's host rock attached to.

 

[rock]

I do have some obsidian as well. They are smaller rocks, about 1-3 pounds a piece. I think I have 5 of them. One does look like it was used as a tool at one point, possibly be Indians in the area. I can upload pictures if you like.

Yeah I would like to see them. We here in my town do have some Flint that looks like that but isnt the same Lithic.