The icicle-like forms shown in Figure 1 were brought to me as fulgurites. They are not fulgurites nor are they stalactites. Fulgurites are hollow and these icicle-like forms do not show the structure of stalactites.
Proceedings of the Iowa Academy of Science
©1956 Iowa Academy of Science, Inc.
Cable, E. J.
"Stalactitic-like Deposits Found in a Gravel Pit in Black Hawk County,"
Proceedings of the Iowa Academy of Science, 63(1), 443-444.
Available at: https://scholarworks.uni.edu/pias/vol63/iss1/45