Description: If making more than one purchase, please read the note following the red text below! Teaching hand specimen of the Valmonte Diatomite, a unit of the Monterey Formation Diatomite or diatomaceous earth is a sedimentary rock composed of the siliceous cage-like shells of diatoms, single-celled algae that live in the shallow water of lakes and the sea. As they die there is a constant rain of their shells onto the seabed and lake bottoms, where they accumulate to form chalk-like diatomite. The shells of diatoms are made of opal, so unlike calcareous chalk, diatomite will not effervesce with a drop of hydrochloric acid. Diatoms extract the silica of their shells from the water they live in. It takes special conditions to form a deposit of pure diatomite - active volcanism makes silica available, while very cold water inhibits the growth of foraminifera, the plankton that have shells composed of calcium carbonate. Diatomite forms in high elevation lakes and in polar seas, and is found where similar conditions existed in the past. This marine diatomite is from the Palos Verdes Peninsula in Los Angeles County, California. It overlies the Altamira Shale, lowest unit of the Monterey there. The Monterey Formation is the source rock for much of the oil produced in California, thanks to the diatoms. Diatomite has industrial uses in filtration, in insulation and cat litter, as a filler in rubber, paint, cosmetics and plastics, as a mechanical insecticide and as a stabilizer in dynamite. It is also used as a polishing agent in toothpaste and as a component of some cement blends. These hand specimens are 1 1/2" to 2" thick. One sample should have between 50 and 100 species. The microphoto shows diatoms extracted from one sample by Anne Gleich. These specimens are collected from an extremely limited exposure. If you want attractive hand specimens for the classroom, enter "lacustrine" in the store search bar, on the right below the photo of the mineral collectors on the home page. That will take you to the lacustrine diatomite we have in stock. 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 black mechanical pencil, a silver and black pen, a silver and blue pen, or one of those plus some number of coins, or you can let us make the selection. Making multiple purchases? Just add items to your cart. When finished shopping, click on "view cart" and then click on “request combined shipping” at upper right in the Shopping Cart window. Do not proceed to checkout. We will send an eBay invoice with the correct combined shipping. Shipping: Priority Mail or Ground Advantage, whichever is cheaper, unless we can find a better rate. Rates vary by weight and zip code. We can usually ship for less than eBay will charge, and will refund the overpayment as soon as the box is packed. International customers: We sell and ship internationally. If eBay’s page does not let you enter your country name to determine the shipping cost for something you are interested in, please contact us. We can tell you what the shipping would cost and how to make the purchase. You can then decide if you wish to complete the transaction. Use the Contact Seller link in the Seller Information box on the right side of this page.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!
Price: 8.2 USD
Location: Olancha, California
End Time: 2024-08-08T21:52:33.000Z
Shipping Cost: N/A USD
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Return shipping will be paid by: Seller
All returns accepted: Returns Accepted
Item must be returned within: 30 Days
Refund will be given as: Money Back
