Basalt, which is one of the most prevalent rock types on Earth, is of volcanic origin. Relatively rich in iron and magnesium, the name of the rock is believed to stem form the Ethiopian term basal, meaning “a rock from which iron can be derived.”

The appearance and structure of basalts may vary significantly, though they are typically dark gray or black in color. Found worldwide amid the oceans as well as the continents, the rocks form when a certain type of magma cools and hardens. Sometimes the result is a smooth, glassy rock, while other samples may instead display a porphyritic structure. Basalts may also be spongy or amygdaloidal. This latter form of the rock occurs due to the deposition of secondary minerals, such as calcite or quartz, in gas bubbles that become trapped within the rock during the cooling process. The term amygdaloidal refers to the characteristic shape of the mineral deposits, stemming from the Latin word amygdala, meaning “almond.”

Though not generally considered one of the more aesthetically pleasing rocks, basalt was the inspiration for a line of stoneware generated by the English potter Josiah Wedgwood. Black, unglazed, and mutely polished, the stately Wedgwood basalt, also known as Egyptian ware, entered the market around 1768. Though sometimes appearing in the form of tea sets and dishes, more often the dark pottery could be found as candlesticks, bookends, plaques, figurines, sculptures, and vases. These items were typically decorated in the neoclassical style that was popular during the period.

Questions or comments? Send us an email.

© 1998-2022 by Michael W. Davidson and The Florida State University. All Rights Reserved. No images, graphics, scripts, or applets may be reproduced or used in any manner without permission from the copyright holders. Use of this website means you agree to all of the Legal Terms and Conditions set forth by the owners.

This website is maintained by our
Graphics & Web Programming Team
in collaboration with Optical Microscopy at the
National High Magnetic Field Laboratory.

Last modification: Friday, Nov 13, 2015 at 01:19 PM

Access Count Since November 20, 2003: 20916

For more information on microscope manufacturers,
use the buttons below to navigate to their websites: