When ordinary negative polarity cloud-ground lightning discharges into a grounding substrate, greater than 100 million volts (100 MV) of potential difference may be bridged.

[2] Such current may propagate into silica-rich quartzose sand, mixed soil, clay, or other sediments, rapidly vaporizing and melting resistant materials within such a common dissipation regime.

Fulgurites are structurally similar to Lichtenberg figures, which are the branching patterns produced on surfaces of insulators during dielectric breakdown by high-voltage discharges, such as lightning.

The interior of Type I (sand) fulgurites normally is smooth or lined with fine bubbles, while their exteriors are coated with rough sedimentary particles or small rocks.

[20] Other materials, including highly reduced silicon-metal alloys (silicides), the fullerene allotropes C60 (buckminsterfullerenes) and C70, as well as high-pressure polymorphs of SiO2, have since been identified in fulgurites.

[32] Over the following centuries fulgurites have been described but missinterpreted as a result of subterrestrial fires, falsely attributing curative powers to them, e.g. by Leonhard David Hermann 1711 in his Maslographia.

[33] Other famous natural scientists, among them Charles Darwin, Horace Bénédict de Saussure and Alexander von Humboldt gave attention to fulgurites, without discovering the relationship to lightning.

In 1805 the true process of forming fulgurites by lightning strikes to the ground was identified by agriculturist Hentzen and mineralogist and mining engineer Johann Karl Wilhelm Voigt.