marble - student specimens of large-grained white marble - Unit of 5 specimens

Description

If making multiple purchases, please read the note following the
red text
below!
Student teaching specimens of white large-grained marble.
Unit of 5 specimens.
This marble is pure white with very large crystals and is a unit of the Devonian Lost Burro Formation. It is associated with cyclically bedded and vertically tilted  limestone, field photos. It was quarried at the Valley Mine in Knight Canyon on the east slope of the Argus Range in the Panamint Valley, Inyo County, California, apparently along with dolomite for roofing or landscaping. The mine, operated by Metalline Industries of Grass Valley, California, has long been inactive. In the 1950s and '60s, gently-sloped ranch house roofs in Southern California were often covered with loose crushed white dolomite gravel.
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 really don't like the tiny finger nail-sized specimens offered to students, as we feel these are too small to see rock textures and too small for examining the identifying characteristics of a mineral. We want the "Oh, Wow!" effect when students see the set of specimens they are going to work with. We collect these specimens so that five specimens, or possibly six, will fit in a small flat rate box, and we keep the price low, as we know these will be used in a classroom. For teachers we count like a baker and a dozen is more than 12, since you will always need a few spares.  If you are a teacher, let us know.
You are buying a unit of five student specimens. The photo is representative of what we ship.
Making multiple purchases?
Just add items to your cart. When finished shopping, click on
“request total”
at upper right in the Shopping Cart window.
Do not proceed to checkout.
We will send an eBay invoice with the correct combined shipping.
The combined shipping will often be less than eBay shows. Please wait for that invoice before paying.
There is no obligation to purchase. You can decide after seeing what shipping will cost.
Shipping:
Ships in a small Priority Mail flat rate box unless combined with other purchases. We always combine shipping to get your purchase to you at the lowest cost. We do not charge for handling. We refund any overpayments on shipping beyond our actual cost. A second unit moves the shipment into a larger box. We can generally ship 4 to 5 student units or a number of hand specimens in that box with no further increase in postage.
Pay securely with your debit or credit card through PayPal! You do not need a Pay Pal account to do this. Yes, we do combine shipping!