Sandstone

Limestone consists largely of carbonate minerals, commonly calcite.

Sandstone consists of sand-sized grains joined into rock.

One name therefore tells us much about composition, while the other draws attention to the size of the particles.

Limestone can contain material made by organisms, including shells and broken shell pieces.

Its texture matters.

A close examination may reveal recognizable remains, fine carbonate material, or crystals that have changed during the rock's history.

Sandstone preserves a different arrangement.

Individual sand grains accumulated before becoming bound together, often by minerals deposited between them.

And then I had a little bolt hole in Ultimo where I'd go and make a mess and then home and suit and tie and face the day, sort of thing.

And was it Sandstone initially that sort of interested you? That was your first sort of foray into creating and making with

Sandstone? I was leading a certain life and the worst...

What was that life? Well, after I...

It's all right.

So, yeah, hacking into it became seriously important.

I

guess your interest and fascination with Sandstone then resulted in a book.

Sediment that was once mud on an ocean floor has been compressed into shale, heated into slate, squeezed further into phyllite, and crushed still further into schist or gneiss.

Sandstone has been metamorphosed into quartzite.

Limestone has been transformed into marble.

The story written in these road cuts is a story of unimaginable force, the force of continents colliding, of an ocean closing, of hundreds of millions of years of tectonic compression squeezing and folding and heating rock until it flows like putty, then raising the whole mass to the sky, and then the equally unimaginable patience of erosion wearing it all back down.

Take a big sandstone block with visible dimensions of 7 metres by 2 metres by 1 metre.

Multiply those and you get 14 cubic metres.

Sandstone in this area averages around 2.2 to 2.4 metric tonnes per cubic metre.

Multiply again and you land somewhere between about 30 and 34 tonnes.

if the same block is actually two meters thick not one your volume doubles and so does the mass now you're in the sixty to seventy ton range change the density a bit and the figure shifts again if one corner is buried or the block is cracked or eroded you're guessing now look at puma punku many of the largest blocks are heavily damaged partially buried or missing chunks Different authors use slightly different measurements and densities.

put them under a microscope and compare grain size mineral mix texture the way crystals grew and interlocked it's like a fingerprint You can go further with geochemistry and isotopes doing elemental analyses that show trace element patterns.

Andesites from one volcanic centre won't be chemically identical to those from another.

Sandstones from different sedimentary basins record different source rocks upstream.

Um, very impressed.

It's better than Sandstone.

Hate to say it, because Sandstone was a big part of my growing up.

Going there as a kid.

Never snuck in.