Description: 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.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.If making multiple purchases, please read the note following the red text below. Agate geode slice from Brazil - hand specimen Agate is a cryptocrystalline variety of quartz - essentially a translucent banded multicolored chalcedony. The colors are caused by impurities - pure agate is white, gray or blue-gray. The banding in this agate is primarily caused by variations in translucency of the concentric layers that follow the wall of the cavity. Normally, agates like these are shades of brown and gray, but blue and green also occur, though not as commonly. Agate is easily dyed, creating slices with an unfortunate rainbow of artificial greens, blues and reds. These slices are natural.In rocks like basalt, which is poor in silica, gas bubble cavities in the solidified lava are gradually filled with a colloidal watery solution of silica picked up from weathered silicates by descending rainwater. Brazilian agates, like these, typically form in cavities in basalt flows and show weak banding but good translucency.Surprisingly, the agate is composed of normally invisible fibers radiating in from the edge of the cavity. They originate from different points in the first agate layer lining the cavity and are microscopic, with identical optical properties and composition. The fibers can be revealed in a thin slice when illuminated from behind by a distant a point light source, in slices thinner than these, ideally thinner than 1 mm. The pattern of fibers can be seen in thin sections of roughly 30 microns (thousandths of a millimeter) when viewed in a polarizing petrographic microscope. Select a specimen: When more than one specimen is shown, you can select a particular specimen by telling us what is in front of it - a black mechanical pencil, a silver and black 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. 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! Click on "Request total" in the shopping cart for a no-obligation invoice to see the total with shipping.
Price: 8.2 USD
Location: Olancha, California
End Time: 2025-01-23T07:48:30.000Z
Shipping Cost: N/A USD
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Item Specifics
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
