UKC

I'm looking to sell a large kitchen table and want to know exactly what it is made of.

I have always assumed it was granite, but some research suggests it might be quartzite.

It is black with grey flecks, very uniform in pattern all along the length, highly polished top, rough unpolished base.

A couple of photos are here,
Top corner, https://i.imgur.com/ThNh3zP.jpg
Base corner, https://i.imgur.com/A4YrQuV.jpg

Could anyone tell me what it is made of so I can advertise it accurately.

Many thanks,

Andy

In reply to ablackett:

No expert and it's 20 years since I had a geology class but I suspect it's too dark for granite, probably some other more basic igneous rock. I'd take that with a pinch of salt, memory is an unreliable thing at times.

I'd sell it as 'black polished stone table (like granite)' if you're that bothered.
jk

In reply to ablackett:
Its certainly not granite or quartzite for that matter. JK is probably not far off, its very hard to tell much from your photo (my guess would be dolerite)
However as geology is complicated decorative stone is usually characterised as either 'granite' or 'marble' so if youre flogging it granite or black granite would most likly do

In reply to ablackett:

Sounds very like the stone from which they make granite surface tables for metrology purposes.

Always called granite by surface table & CMM manufacturers and I believe mostly sourced from France

In reply to ablackett:

Gabbro?

cheers
mark

In reply to JMarkW:

https://en.wikipedia.org/wiki/Granite
"The rock known as "black granite" is usually gabbro, which has a completely different chemical composition.[30][31]"

In reply to ablackett:

sounds like calling it 'black granite' would be fine

https://en.wikipedia.org/wiki/Black_granite

In reply to ablackett:

Could be basalt? Just like the Edinburgh cobbles

In reply to JMarkW:


Yeah, Gabbro

In reply to ablackett:

As others have said black granite is fine. It's a catch all description of several rock types. http://www.stonespecialist.com/news/stones-quarries/building-stone-black-gr...

In reply to ablackett:

That's the crux of three pebble slab (HS)

In reply to ablackett:

Not possible to tell from the photo but, to echo others, it's not granite, certainly not quartzite (would be white!), and the grain size is too large to be basalt.

If the lighter crystals include any faint stripes, then it's most likely a dolerite or a gabbro (much the same thing). If the white stuff comprises two slightly different colours (something milkier with those stripes and something slightly translucent with no discernable internal structure, possibly in small roundish crystals) then it's possibly a dacite. Hard to tell from those photos, though.

None of which matters for selling, but it might be nice to try and figure it out...

In reply to ablackett:

It bit dark for my fancy but I'd advertise it as:-

"Lovely dark granulated dirorite crystal table. Excellent polished top in perfect condition"

In reply to ablackett:

What would a new one be described as on Amazon / Magnet or whatever? Use that.

In reply to ablackett:

Um, fascinating.

In reply to ablackett:

It could be any one of a number of basic, intrusive igneous rocks (which definitely rules out granite and quartzite) so gabbro or even peridotite is in the right area but if you want to be really accurate then you would need to look at a thin section under a microscope!
These days "granite" has become a generic term for anything crystalline and shiny so unless you're aiming to sell it to an igneous petrologist then calling it anything other than "black granite" (even though no such rock exists) will only cause confusion

In reply to ablackett:

I was wondering if it could be this stuff.

https://www.silestone.co.uk/what-is-silestone/

It suggests that it is 94% quartz but can be black. Manufactured "manmade stone".

Sounds like it doesn't matter much either way but if anyone had a sure fire way of telling if it was the natural stuff or the manmade stuff I would appreciate it.

In reply to ablackett:


That sounds a lot like branded concrete.

Yours is most likely a fine-medium grained basic intrusive igneous rock, there's a whole family of them.
jk

In reply to ablackett:

What your referring to is commonly called terrazo. Its made od chippings of actual rocks set in concrete. Without some degree of geological knowledge it can be hard to tell apart from real rock. Does the fine bits inbetween the larger bits look like concrete?

In reply to ablackett:

Posted on ebay now, 232282904394 if anyone would like a look.

In reply to jkarran:

Not quite, its ground up quartz bonded with a type of resin, a bit like fragranite or composite granite (but with quartz and not granite). It does look like some kind of quartzstone (manufactured) to me.

In reply to ablackett:

Silestone and such-like are often thinner than Granite - there's no natural faults in them and thus don't need to be so thick.