The first comprehensive analysis of what the sarsen stones are made of came about with new technology—and good old-fashioned luck.
Scientists have long interpreted shocked quartz as definitive evidence of a past meteorite impact, but the shock wave caused by lightning striking granite also produces this distinctive feature.
Using Puerto Rico's Luquillo Mountains as a case study, scientists use the region's geological history to study how knickpoints—areas where there's a sharp change in the river's slope—move over time.
A comparison of water content in undeformed and deformed quartz indicates that grains may change shape via weakening processes that cannot be duplicated in laboratory experiments.
Studies of titanium in quartz grains could help scientists gain a better understanding of our planet's shifting surface.