Answer: "Stuffing, mostly!" (with apologies to Winnie-the-Pooh

This thread is basically another look at the filler material from the resin component of J-B Weld STEEL epoxy, prepared by washing with acetone as I described in the Microscope forum at http://www.photomacrography.net/forum/v ... 596#172596.
Here's the view at highest magnification, in stereo. These are crops from a stack shot at 20X on a Canon T1i with APS-C sensor. The uncropped frame width is about 1.1 mm; these crops are about 0.3 mm wide.


In the crops, especially in stereo, you can see how exquisitely thin some of the red flakes are.
Here's the whole frame at 20X, 1.1 mm field width. If you go looking for the crops, be aware that I rotated those 90 degrees so that I could capture more interesting stuff in each vertical-format display.

Now we'll work out to lower magnifications, to get more context. In each image, I've outlined the approximate area covered by the previous image.
10X:

2X:

Compact point-and-shoot.

The filler material is lying in the corner of that round-bottomed glass, which in turn is propped at an angle so that a vertical lens can look down somewhat obliquely onto the surface of the material. The trench that we're looking into is where I reached in with forceps to get the sample that turned into the microscope slide linked earlier.
Illumination was by Ikea Jansjö LEDs diffused through latex glove fingertips and further diffused by Kleenex tissue around the specimen.
--Rik