The slab, measuring 24.1 by 20.1 centimeters, is made from locally sourced vesicular basalt, matching the geological composition of rocks in the ... symbols are not found in any language known ...

Such rocks are said to be vesicular and the rock name is modified by vesicular (example vesicular basalt) Quiz 2 is next week on MIneral Identification - be sure to look at the quiz info on the class ...