.
Questions and phone orders: 10 AM - 10 PM Pacific (760) 920-6465

tuff - copper-stained green welded tuff - teaching hand/display specimen

$ 7.50

This particular volcanic igneous rock is composed of volcanic ash and fragments of other igneous rocks (clasts) that were ejected from a volcanic vent and then welded together. Copper has stained it green.

Tuffs are light colored, usually shades of buff or gray, and since they are silica rich, they are not dense. A green tuff is unusual. This one has the typical angular rock fragments that were ripped from the walls of the vent welded into the ash. A student should know these fragments as clasts, from the Greek klastos for broken in pieces, and should know they are characteristic of tuffs.

If you are a science or earth science teacher purchasing this as a teaching specimen for your class, this should be compared with other silica rich volcanic igneous rocks, tuff breccia, pumice (which is so full of entrapped gases that it floats in water) and rhyolite (extruded as lava) and with silica rich plutonic igneous granitic rocks. A tuff breccia will have larger clasts of various igneous rocks than does this tuff.

Field photo is of assistant, T Cat, pretending to be Atlas.

 

 

 

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 and silver pen, a black mechanical pencil, a blue and silver pen, or one of those plus some number of coins, or you can let us make the selection.

Shipping: By Priority Mail or USPS Ground Advantage. Click > here < for shipping rates. See comment at Note! Use back button to return to this page.

Hand/display specimens are hand-sized but are thicker, around 2" to 2 1/2" in thickness.

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.