Somewhat more than 10% of the rock is composed of metal grains.
Then the worm drops metal grains around its food block, and we sweep them up.
CB (subgroup a) chondrites are coarse grained, with large, often cm-sized chondrules and metal grains and almost no refractory inclusions.
Kim, Y.E. (2009) "Theory of Bose-Einstein condensation mechanism for deuteron-induced nuclear reactions in micro/nano-scale metal grains and particles," Naturwissenschaften 96(7):803-11.
In Phase I the lunar regolith would be raked for metal grains, which would then be reduced to their component elements by the gaseous carbonyl process.
They have the advantage that the flux is always oriented parallel to the metal grains, reducing reluctance.
The two processes - growth of bubbles and metal grains - are mathematically almost identical.
Even when material scientists know of a desirable arrangement of metal grains, they have to discover by experiment a process that can produce it.
For instance, last fall, the Eurex, a British electronic exchange created only nine years ago, supplanted the Chicago Board of Trade as the dominant exchange for metal, grain and financial futures.
He delved into the structure of inorganic matter, starting by analyzing the shape of metal grains, and eventually developed a general theory of structure as hierarchy.