Amino-like nitriles/cyanides and heterocycles are also found. These related organics may be decomposition products or precursors. The early analyses did not record optical rotation, and gave meteoritic organics as racemic. As amino acids are diverse but low, the discovery of meteoritic chirality had to await the separation of IOM. Handedness of some meteorite organics is now accepted (see below), including in the soluble organic fraction. Kvenvolden et al. 1970; 2. Meierheinrich et al. 2004 3. Martins et al. 2015 4. Koga et al. 2017; 5. Rudraswami et al. 2018; 6. Pizzarello, Yarnes 2018  The first publication of anomalous gas in a carbonaceous chondrite (Murray) was in 1960. "Gas-rich meteorites" of other classes host their gas in dark liths, in most cases closely related to CM. Gases in meteorites include primordial, solar (both solar wind, and a distinct solar flare component), radiogenic (due to cosmic-ray exposure), and fissile (decay products). Host materials are generally carbonaceous, including presolar grains: diamond, silicon carbide,, graphite, and organics. Nogoya is one particularly gas-rich CM chondrite. Micrometeorites lose significant amounts of their gas to entry heating, but still deliver quantifiable amounts. Isotope studies have become vital in examining natural histories. Oxygen, in particular, forms quite stable oxides; it requires significant events, processes, or energies to segregate isotopes by their slight mass differences. CM and CI chondrites have a measurable difference in oxygen isotope levels. This suggests a different formation temperature, and hence a different zone of the young Solar System. However, CM and CO meteorites were found to have similar oxygen isotopes, indicating a relationship. CMs, like other C-chondrites, are subjected to a serious observation bias. C-chondrites are friable, due to both macro-scale porosity and micro-scale matrices of phyllosilicates, with many chondrules also having layers such as phyllosilicates. The meteorites have been described as "tuff" (compacted volcanic ash). As one example, the Tagish Lake meteorite provided ~10 kg of samples, from a meteor estimated to be 60-90 tons before entry.