Dr. CJ Ransom and Wal Thornhill published a paper with IEEE describing an electrical experiment which successfully produced small hematite spheres, very much like the Martian Blueberries seen by the Rover Opportunity at Meridiani Planum on Mars.
When iron oxide, quartz sand, and lava sand were exposed to a plasma discharge for 5 or more seconds, small spheres were consistently formed. These little lab created spheres elicited such astonishment and wonder, for me, that I have spent much of my spare time and resources both having additional experiments carried out, and searching for any possible naturally occurring examples of the spheres.
In particular, sometimes the lab created spheres were in a double or triple form; the double spheres were seen in the original published paper, and the triple, joined spheres were created in an experiment carried out later in the same process, using lava sand.
By June of 2012 I was blessed to publish a small paper (through an alternative science association) which laid out the groundwork for the continued investigation into the possible rapid, electrical formation of soft-bodied fossil concretions. For many reasons, I felt these compared very well with lab-created stone spheres. Here in the northwest there are many formations with crab, shrimp, and brittle star fossils, three dimensionally preserved inside of concretions. There is typically not much breakdown of these crustaceans. Besides having a very lifelike fossil as a nucleus, the sandstone spheres have many other consistent features. I also visited fossil sites in other states, such as the Mazon Creek Formation in Illinois. Along with a lot of other physical evidence for rapid, electrical formation of fossil-bearing concretions, I found a number of double, that is, fused spheres which contained the same beautiful soft bodied fossils as the singles.
Over the years, my collection grew to include double and triple fused spheres from all three rock types -- sedimentary, metamorphic, and igneous. I would be pleased to share these with you, as a way of bringing some completion to the findings. I have also gathered examples of another electrical process that easily forms double and triple spheres. I should mention that electrically produced spheres are often hollow, as well.