query for chemists...
 

if we have any? I know we have physicists and mathematicians!

Is it positively wrong to refer to gypsym as lime?

Weird question, I know. Grateful for any responses.

Although I am emphatically not a chemist, I find that doing a google search under the words "gypsum lime" will get you a lot of chemical information about both gypsum and lime. As far as I can tell, they will do similar things to the soil but neither one is a subgroup of the other.

I'm a chemist, but I must have been sick that day.

Wiki to the rescue: Lime can refer to calcium oxides, hydroxides and/or carbonates, while the mineral gypsum is composed of calcium sulfate. So they're different compounds.

Both are ingredients of building materials. Calcium carbonate is a major component of cement, gypsum a minor one. Although there's such a thing as lime plaster, "plaster" commonly refers to plaster of Paris, which is made from gypsum.

So "gypsym" is a typo, then? Or just a funky Hellenization?

I work in the building materials sector, and while I am not a chemist, I know for certain that gypsum and lime are completely different products sold separately. Also, gypsum is often used in reference to wallboard or gyproc etc., so if you were planning on using the term poetically, bear in mind the many connotations of the term...

Yup, gypsum and lime are definitely different. I know because a few months ago my kids wanted to make limewater to use as a carbon dioxide indicator (limewater precipitates calcium carbonate within about 15 seconds in the presence of carbon dioxide).

The instructions in the book we were using (Oxidation by TOPS Learning Systems--we absolutely love their whole series) were, "Prepare limewater from hydrated lime (also called calcium hydrate, calcium hydroxide, and garden lime). Purchase in as small a quantity as possible from garden supply or farm stores. Lab grade purity is not required. The solubility of this powder in water is very low. Stir in a level teaspoon (4 mL) into a quart (or liter) jar of water, then close with a lid and allow the chalky white mixture to settle about 24 hours. (Limewater left exposed to carbon dioxide in air forms a heavy surface film of calcium carbonate.) Pour off the clear liquid into a second storage jar with lid and label it LIMEWATER (CaOH2). Add more water to the sediment in your original jar, and set aside to resupply your labeled jar as needed."

Alas, San Diego's soil is so incredibly alkaline that none of the garden supply stores here carry lime as a soil supplement. I couldn't order less than a 50-pound bag from elsewhere, which I refused to do for my kids because I'm just a bad parent, I guess. The local home improvement stores had plenty of gypsum, which would not have worked because that's calcium sulfate, not calcium hydroxide.

Say! If any of YOU out there in the 'Sphere have acid soil, I'd be willing to pay you to send us a teaspoon or so of lime. My daughters are still bummed out about skipping the set of experiments involving limewater, because the other experiments in that book are so much fun. Just this week the kids went to a friend's house and repeated the pyromaniacal steel-wool-and-clothespin sparkler demo (with parental supervision, of course.)

Julie Stoner

Another cheery thought before I skip off to bed...

Lime is the stuff shoveled into mass graves, and also contained inside a sarcophagus (hence the "flesh-eating" etymology, and some sarcophagi were actually carved of limestone)...presumably because lime would hasten the decomposition process and reduce the danger of disease, odors, etc.

I doubt that gypsum would have the desired effect.

Hi Alicia,

As an editor for the flagship magazine of the American Chemical Society®, I would say that, chemically, gypsum and lime are close enough for jazz. Poetry, as you know, is the art of proudly approximating science, but only when you have to. You're going to get some really long letters from 40-year ACS members, but, believe me, they have nothing better to do than to write long letters.

Green light,
Rick

Thanks all so much for this! This forum has amazing resources!

I'm interested in what acid rain does to marble--I realize it turns it to gypsum (sorry about typo--at any rate, gypsos is Greek for plaster)--sort of chalky crumbly white stuff--but wondered if for poetic purposes I could describe that as lime. I have an alternative line if need be, but lime works better poetically, if not scientifically. Still, it is one thing to be vague and another to be inaccurate.

You're not writing science, you're writing a poem~,:^)

No kidding. Lime is a term you can use loosely. It's familiar as a chippy white material. Really, go with it. I don't know how many times I've seen good poetry wrecked by good science. I don't know how good it is, but I wrote a poem called "Wild Mustangs" about horses in North Carolina that my biologist brother-in-law insists are feral mustangs because they are only truly wild in Europe, their original habitat. He's right, and I feel sorry for the poor guy.

Rick

NB: I remember now that I changed the title to "Spanish Mustangs." But that's irrelevant.

Thank you, thank you, thank you, everyone. (Though I'm going to quote you, Rick, if I get any complaints about the poem! No good deed goes unpunished...) Stay tuned...

I think you can be pretty safe with 'lime', but it might depend just a little on the context (well, obviously). I can only speak for the UK, but while masonry was rendered with plaster as long as I have witnessed it - and probably still is - you'd only have to go back a generation or so to the time when interior walls were rendered with horse hair and lime. I believe it was not as strong as plaster, which is why you had dado rails and high skirting boards and such to stop the furniture from making big holes in it.

Be that as it may, lime was, and therefore can/could be, used in much the same way as plaster.

But it doesn't rhyme as well with alabaster.

http://www.oldhousestore.co.uk/produ...lo_LPLR0010001

er - or you might feel more at home with this one...

http://www.heritageconservation.net/...ir-plaster.htm

Not that it helps, but lime is also a commonly used term for the sort of whitewash that Greeks apply to their houses, sometimes called Asvesti in Greek (asbestos, though not at all the same thing). One limes the walls of a cottage. One limes the trunk of a plane tree. Anybody else familiar with this? I did a hell of a lot of liming when I was young.

"a little, lime-white cottage in the corner of the glen" - Flann O'Brien

So when you limed beneath something, was it sublime?

Sea goers used to use it, did they not? Lime of the ancient mariner?

Okay, okay. I'll stop.