In 1984, Witten pointed out that matter made of up, down, and strange quarks would be more likely to be stable than matter made of just up and down quarks. This is becuse the potential energy is about the same in both cases, but the Pauli principle doesn't require as much kinetic energy in the strange quark case with three different kinds of particles, rather than two. We know that quark matter with just up and down quarks is not stable because nuclear physics teaches us that the quarks bunch up into protons and neutrons and the material falls apart into separate nuclei. In the three quark case, there is a chance that macroscopic bodies exist made of up, down, and strange quarks and having nuclear densities: 10^{14} grams per cubic centimeter. Stuff this dense is hard to detect and hard to make.
I will review the basics of strange quark matter structure and phenomena, some of the arguments against it, some of its terrestrial signatures suggested by de Rujula and Glashow, and two methods for searching for it in which I am involved. One uses seismic signals emitted if a nugget of it, with mass of more than a ton, passes through the Earth. The other uses a narrow-band, millimeter-wave radio signal at a characteristic frequency that might be emitted from pulsars if they are made of strange quark matter. In the time remaining, we can work as a group on the question of other ways of finding it.