Surface features of around 3 5 nm in diameter are observed in all pristine samples of different thicknesses, which can be attributed to nanocrystallite-induced roughness on the surface.
In any case, Borg and his colleagues "have done a fantastic job of putting together a beautiful study of this rock, one of the most pristine samples of early lunar crust," he notes.
There are places, such as in Cornwall in southwest England, where chunks of ancient Moho have been thrust to the surface, but it remains a key quest for scientists to drill down and retrieve pristine samples of rock from either side of the discontinuity.
Comets are dark objects of ice, dust and rock that are believed to contain pristine samples of the material from which the solar system was formed some 4.6 billion years ago.
The Sutter's Mill meteorite is the most pristine sample yet collected of a rare type of carbonaceous chondrite, and possibly a sneak preview of a primitive asteroid to which NASA might one day send astronauts.
A concise series of five cycled samples, as well as a soaked and pristine sample, were measured at different states of sodiation after the initial sodiation and after the following full cycle of sodiation and desodiation.
Thus, we emphasise that for any quantitative analysis of leachate compositions, the collection of pristine samples is of absolute importance, and echo the recommendations of the 2013 IVHHN guidelines in that researchers must 'try to collect tephra in a pristine (dry, not rained on) condition'.
The first one, at about 60°C, is sharp and similar to that of the pristine sample; an additional broad endotherm is seen at 130°C, indicating the formation of the second crystalline phase, which is absent in the pristine sample.
The surface of the pristine sample is smooth with a rms roughness of 0.2 nm. Figure 2 shows the surface morphology of the samples irradiated at different angles of incidence with respect to the surface normal using 100-keV Ar+ ions with a fluence of approximately 3 × 1017 ions/cm2.
