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Apollo 11

Apollo 11 lunar sample types

The Apollo 11 Preliminary Science Report classified the returned lunar material (~22 kg, split roughly half above and half below 1 cm in size) into four groups:

  • Type A — fine-grained vesicular crystalline igneous rock. Gas cavities (vesicles) and bright crystal-lined vugs; mineralogy dominated by clinopyroxene (~53%) and plagioclase (~27%) with abundant opaques (ilmenite, troilite, native iron, ~18%) and minor olivine.
  • Type B — medium-grained crystalline igneous rock. Granular, microgabbro-like texture; clinopyroxene (~46%), plagioclase (~31%), opaques (~11%), cristobalite (~5%); no olivine.
  • Type C — breccia. Mixtures of angular fragments and glass spherules, welded by shock; evidence of strong shock is common, indicating formation by impact lithification of the powdery surface material.
  • Type D — fines (< 1 cm). The regolith soil: ~50% glass (of several colors and forms, including spheroidal/teardrop shapes), plus plagioclase, clinopyroxene, ilmenite, olivine, and Ni‑Fe spherules.

Types A and B are the high-titanium mare basalts; types C and D are impact products of the regolith. All four are chemically similar — rich in refractory elements, poor in volatiles and water — with no close terrestrial equivalent. The fines and breccias also carry abundant implanted solar-wind rare gases.

Per-sample study compiled in the Lunar Sample Compendium maps these groups onto the modern collection: the crystalline rocks split into high-K and low-K ilmenite-basalt suites (the largest being 10017 and 10057); the breccias are almost all regolith breccias (shock- lithified soil, e.g. 10046, 10060); and the fines are typified by 10084 and 10002.

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