Was Libyan Desert Glass formed by a sol-gel process?

Abstract

Despite extensive research for nearly five decades, the origin of Libyan Desert Glass remains a puzzle. It is suggested that this glass was made by a low-temperature, chemical process known to have produced other natural glasses, such as opal. This new genesis is based upon a periodic void spacing observed in this material and irreversible changes that occur upon heating, especiahy crystallization and consolidation. These features are seemingly irreconcilable with a melt-derived origin for Libyan Desert Glass, but are consistent with a low-temperature chemical mode of formation.