marble - teaching hand specimen of large-grained white marble
This marble is pure white with very large crystals. It is a unit of the Late Proterozoic Johnnie Formation and is being mined for cement-making. These specimens were collected at the Piercy Quarry near Victorville, San Bernardino County, California.
Marble and dolomite can look similar. Marble is calcium carbonate, derived by metamorphism from limestone. When further metamorphism adds magnesium, the result is calcium-magnesium carbonate, dolomite.
In the field and in the lab these two metamorphic rocks can be identified by their differing reactions to dilute hydrochloric acid. Marble strongly effervesces. Dolomite effervesces weakly or not at all, and strongly only when powdered by a few taps of the geologist's hammer. The difference will be obvious to students in the lab.
It would be instructive to compare this marble with a large-crystal dolomite. It can also look, at first glance, like a granitic rock missing the dark minerals. The granitics will not effervesce and they are much harder.
We often have this marble in hand/display specimens also. What's the difference? The hand/display specimens are thicker - too thick for a small flat rate box. If you're ordering a single specimen, stick with the hand specimens for cheaper shipping. Buying more than one item? Take look at the hand/display specimens, since they can share their box. We combine shipping.
Select a specimen: When more than one specimen is shown, you can select a particular specimen by telling us what is in the photo with it, a blue or black and silver pen, a black mechanical pencil or one of those plus some number of coins, or you can let us make the selection.
Making multiple purchases? Click on the "combine shipping" button in the shopping cart. We'll send an invoice with combined shipping. A link in that invoice will bring you back to checkout, no hassle.
Shipping: Priority Mail small flat rate box unless combined with other purchases. Click > here < for shipping rates. Use back button to return to this page.