scoria - display specimen of maroon scoria from a satellite cone on Mauna Loa
Scoria is the silica poor equivalent of pumice. Lava with a low silica content is runny, so gas bubbles tend to coalesce to form larger bubbles in basalt. In a silica rich granitic magma, high viscosity prevents bubbles from coalescing, so there are many more, but smaller, gas bubbles in pumice, one reason it floats longer in water. These scoria specimens are surprisingly light and are amazingly red from the oxidation of hematite. They were collected at an elevation of 10,500 feet on the north slope of Mauna Loa, from a mass of blocks, scoria and cinder associated with a satellite cone that was quarried for road material. These specimens ship in a Regional Priority Mail box and can be combined in that box with other purchases.
Select a specimen: You can select a 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.
The specimen with a black pencil and 2 coins is scoriaceous - somewhat dense for scoria - and has an interesting "lava" surface.
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.