What kind of rock is this? Why is it so round?

The posts about out of place rocks reminded me that, as a child, I saw some huge out of place rocks on one of the little island (Salt Spring, Pender or maybe Hornby) but I can’t find it now. I remember one of my classmates saying “a volcano exploded miles away and these rocks landed here”. It was one of those moments that really made an impression on me. It probably started my interest in rocks.

I’m always finding rocks and bringing them home but just enjoyed looking at them. It’s very recently that I’ve wanted to know what they are.

If it’s granite, it’s no coprolite (fossilized poop).

As others have said, wave action subjects rocks to lots of abrasion, and causes rocks on the ocean shore to be nicely rounded.

One way for a rock to end up very round far away from an ocean is if it gets caught in a hole under a waterfall or the like. It gets continually tumbled and abraded about equally from all sides.

Does it show any signs of wear or lots of small chipping/scratcing on one side or in a specific spot?

Everything on the earth is old or recycled. Every breath of air you take has a statistical probability of including some molecules that Abraham Lincoln or Charlemagne or Julius Caesar or Og the caveman also breathed.

My teeny little mind finds that even more amazing.

It really does. It fits naturally in my right hand and at the bottom, slightly to the left, is a small, chipped out area. That area is also slightly discoloured. The whole rest of the rock is smooth. Here are a couple more pictures. You can see it in my hand and the area at the bottom.

Imgur
Imgur

The reason I found it is my dog went to do her business about 30 feet off the trail in the underbrush. She’s had a little bit of diarrhea so I made my way over to where she went and saw it buried about halfway in the mud.

NO! What if it’s a Horta?

I know, right? I have a very smooth rounded river rock, sort of a somewhat flattened egg shape, fits my hand very well, and something about the size, shape, weight of holding it is–as you put it–very plesant for some unexplained reason. I wonder if hominids have some unexplored “like holding rocks” instinct?

(I have lately been using it as a hammer stone on almonds and Brazil nuts with another, larger river rock as the anvil–which left no marks because the two stones didn’t hit each other, only the nuts.)

It seems likely, or ar at least possible, that what you have there is a hammerstone

But it could–in theory–have once been a gastrolith. Not likely, but some dinos, at least, had them.

It seems likely that this is a human tool of some kind. Either shaped by hand or found and modified. Vancouver Island is a very resource rich environment and there were large populations of indigenous people there for thousands of years.

Nope (no foliation) and nope (not enough dark minerals) to both of those.

Just being in a fairly energetic river will do it.

That does look like a hammerstone in those photos.

That’ll round off the edges and corners, but won’t necessarily make it [round.

Gastroliths are usually highly polished.

No, it will. Not spherical, but rounded. The two being different things.

On Earth Horta’s would be considered an invasive species. We have enough problems with feral pigs, a colony of feral Horta’s, with their overaggressive mothers, would be significantly worse.

We already have the Horta on earth.

They’re more closely related to humans than they are coral or urchins or anything like that.

Man would I love to find one of those. I went for my evening walk and it took way longer than normal because I was picking up and looking at every rock.

“Is that a Gastrolith??” Nope “Is that a Gastrolith???” Nope…

:smiley:

I’ve wondered if any of these meteorites ended up as ostrich gastroliths.