clasts in these breccias are pieces of older breccias, documenting a repeated history of impact brecciation, cooling, and impact. Regolith breccias resemble the glassy breccias but have little or no glass (melt) to weld them together. As noted above, the basin-forming impacts responsible for these breccias pre-date almost all mare basalt volcanism, so clasts of mare basalt are very rare. When found, these clasts represent the earliest phase of mare basalt volcanism preserved. Mare basalts Mare basalts are named as such because they frequently constitute large portions of the lunar maria. These typically contain 18–21 percent FeO by weight, and 1–13 percent TiO2. They are similar to terrestrial basalts, but have many important differences; for example, mare basalts show a large negative europium anomaly. The type location is Mare Crisium sampled by Luna 24. KREEP Basalts (and borderline VHK (Very High K) basalts) have extraordinary potassium content. These contain 13–16 percent Al2O3, 9–15 percent FeO, and are enriched in magnesium and incompatible elements (potassium, phosphorus and rare earth elements) 100–150 times compared to ordinary chondrite meteorites. These are commonly encountered around the Oceanus Procellarum, and are identified in remote sensing by their high (about 10 ppm) thorium contents. Most of incompatible elements in KREEP basalts are incorporated in the grains of the phosphate minerals apatite and merrillite. Curation and availability The main repository for the Apollo Moon rocks is the Lunar Sample Laboratory Facility at the Lyndon B. Johnson Space Center in Houston, Texas. For safekeeping, there is also a smaller collection stored at White Sands Test Facility in Las Cruces, New Mexico. Most of the rocks are stored in nitrogen to keep them free of moisture. They are handled only indirectly, using special tools. Some Moon rocks from the Apollo missions are displayed in museums, and a few allow visitors to touch them. One of these, called the Touch Rock, is displayed in the Smithsonian National Air and Space Museum in Washington, D.C. The idea of having touchable Moon rocks at a museum was suggested by Apollo scientist Farouk El-Baz, who was inspired by his childhood pilgrimage to Mecca where he touched the Black Stone (which in Islam is believed to be sent down from the heavens). Moon rocks collected during the course of lunar exploration are currently considered priceless. In 2002, a safe was stolen from the Lunar Sample Building that contained minute samples of lunar and Martian