red rock with white vein

Corning, CA(Zone 8a)

Has anyone ever seen one of these before? red marble? or chert..... jasper? Im in Tehama County, California.

Thumbnail by leeannconner
Calgary, AB(Zone 3b)

Here's a really basic test which you can do on all your rocks to, at least, identify or rule out if it is limestone. Calcium carbonate (CaCO3) is the chemical formula for calcite, which is the mineral that makes up limestone and marble (which is metamorphosed limestone, in which recrystallization has taken place). Calcium carbonate fizzes in acid. So, get yourself some 10% hydrochloric acid (NOT STRONGER... and be careful with it even at that strength) and drip a bit on the rock; if it is limestone, it will fizz vigorously.

Having said that, the rocks don't look to me like marble, although the vein-filling substance may possibly be calcite.
Wetting the rocks is not helpful for identifying them; it just creates reflections off the surfaces. The rocks should be dry before you do an acid test or examine them under a hand lens or magnification. Hope this helps.

Gladstone, OR

A much safer test for rocks containing Calcium carbonate (CaCO3) is acetic acid (household vinegar):

10% hydrochloric acid is not readily available to the average person and caution must be used when handling it (eye protection, acid resistant gloves, etc.) but it is available online ( and is useful for testing for gold (

Calgary, AB(Zone 3b)

Notwithstanding my earlier disclaimer, as one never knows what someone else might do...
Nrowlett, you're really overstating the risk in using 10% HCl... it would burn if you got it in your eye, but is otherwise a low risk acid that is a standard in geology work and I've certainly never seen anyone wear gloves while using it (or eye protection for that matter). Note that testing involves putting a drop of 10% HCl on the rock sample from a squeeze bottle, not splashing around vats of it.
And it does not dissolve gold... you'd need a concentration a great deal higher than 10% to do that.
One can get 10% HCl sold as "muriatic acid" at home centers... check the stated concentration, of course.

NB. I just looked up typical vinegar (acetic acid) concentrations for household use - 4% to 8% is typical, apparently - and nobody wears gloves while handling it - so consider that in comparison to 10% HCl.

This message was edited Nov 29, 2011 4:09 PM

Gladstone, OR

10% hydrochloric acid : never used it. Your own statement "10% hydrochloric acid (NOT STRONGER... and be careful with it even at that strength)" would imply that some precaution should be used, so I assumed that would mean rubber gloves and eye protection.

You're right - nobody uses gloves while handling household vinegar, which is why I suggested using it as a test for Calcium carbonate (CaCO3) instead (which I have done myself, so I know that works perfectly well) and it saves me having to purchase 10% hydrochloric acid.

The info on
"Purchase hydrochloric acid or sulfuric acid, rubber gloves, and protective eyewear from a hardware store. Use something like a small piece of glass to drop a very small amount of acid onto the gold. If the gold begins to dissolve, then there is some other type of metal mixed with the gold and it is not pure."

Never did this either so I can't verify it. Just quoting from the web. I have had gold items tested at pawn shops where they use an acid as a test for gold ... another kind of acid?

Calgary, AB(Zone 3b)

My caution was for the reason I stated... who knows what someone might do. In other words, 10% HCl is safe to use for the intended purpose (but on the other hand, it's probably not a great idea to bathe in it or gargle it); concentrated HCl is definitely NOT safe.

Corning, CA(Zone 8a)

Thank you both for your comments I lost my pass to the subscribers forum and was not able to reply back. I just found a limestone deposit on our property so this will be a fun test with the vinegar.. i will stay away from the strong stuff.. as im just a rock admirer.... I did find out they are jasper.. very hard.. we have a variety of jaspers.. one of which appears to be a stomatolite jasper... have you seen this kind before?

Thumbnail by leeannconner
Calgary, AB(Zone 3b)

Absolutely no indication of stromatolites in that rock, sorry.

Corning, CA(Zone 8a)

ok thanks.. i was thinking the algae kind.. but yeah i figured i got it all wrong... :)

Lucketts, VA(Zone 7a)

Leeann - if you live in or near Corning, CA, you live in the middle of the Sacramento Valley. The entire valley floor in that area is composed of deposits of debris washed from the Coast Range on one side and the Sierra Nevada on the other. You would have to go many miles to the east or the west to find any exposed rock units, so it is unlikely that there is a "limestone deposit" on your property. You might go to your library and find an introductory text on physical geology. As you learn more, the rocks you find will be more interesting because of the stories they can tell you. Understanding the basic geology of that area of your state can lead you to nearby locations where you can find a variety of rocks to "admire".

Corning, CA(Zone 8a)

greenthumb99 thank you for the great advice... i never really considered the facts that water, would move things around nor did i consider that the entire valley floor was once under water... Thank you for the great advice... I am studying on the geology of the area.. so i dont waste people time here.. thanks.

Magnolia, TX(Zone 8b)

That area also contains granite deposits, Corning is closer to Redding than Sacremento. Don't know much more than that, but the chert in Ore is a blue blac greenish color, I wonder what color the chert - if any - is for your are?

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