Ms. Napier spotted this sphere in an antiques, minerals, and curiosity shop yesterday and bought it for me, at the price of “$18 for pair” though nobody could find its supposed mate. I can’t figure out what it is.
It is pretty accurately spherical, 2.315 inches or 58.8 mm in diameter according to my shop calipers. It has dark specular metallic lustre and looks a great deal like hematite. It feels dense enough to be metallic (density would be a great clue but I don’t have access to a sensitive scale; I’d guess 1 or 1.5 lbs). It attracts a magnet, but much more weakly than iron does. On a 2 k ohm scale it does not register any electrical conductivity, though on a 200 M ohm scale it sporadically produces numbers and overranges – I wonder if this is a capacitive effect, as I can’t get it to steadily produce a numeric reading. It seems to be as perfect a sphere as I can detect by turning it over and watching distant objects’ reflections, as there is no rippling or waviness effect. I’d say its thermal effusively was like glass, certainly between copper and polymers. My cheap USB microscope seems to reveal a finely granular surface like a sintered metal powder.
Most intriguingly it has scars that appear to be cracks or contiguous voids in the graphite-like exterior, that appear to show the exterior is a coating or layer a fraction of a millimeter thick, with a distinctly orange-red layer under that and a duller light tan layer or body below that. I think the orange-red layer is too vivid, too glossy, too nonporous looking, to be iron oxide. In most places the scars are not very noticeable and look to me like the surface shrank and parted, but contiguous with these areas there’s a deeper scar that looks more like a gouge nearly a millimeter deep.
Waiting for a picture (not that I know how to accomplish that on the Dope). And yabob is right about darning eggs. Had the need to use one way too many times. Glad socks became cheap enough that I no longer had to.
Here’s a photograph. My mystery sphere is on the left. For comparison there is a ball bearing in the middle. Ball bearings seem to be available in a variety of materials but it appears stainless steels, and also steels alloyed with chromium and molybdenum, are very common and I guess would look like this. It is very obvious by hefting these that the mystery sphere is lighter in weight. Also for comparison on the right is a somewhat larger sphere of zinc, which is obviously not as spherical as the first two; it was a gift, bought as a “zinc cannonball”, which I suspect is a plating ball for zinc electroplating.
The mystery sphere has surface flaws, depressions, that look like cracks in the coating or in the worst case like a gouge. The worst such flaw is positioned slightly left of center running upward, and it is between the two brightest highlights (which are reflections of ceiling lights in my shop).
I am sure this is not a hematite sphere, because of these surface flaws. It is clear that the dark metallic sheen is a coating, and that two different shades roughly similar to terra cotta lie below it. The larger surface flaws will catch and hold my fingernail, and they are depressions.
Here is a microscope photograph of the worst surface flaw in the mystery sphere. I took this with a $30 USB microscope I just bought, which is I guess a pretty nice computer interfacing video microscope considering it’s the price of a half dozen fast food burgers. My best estimate of the widest spot on this flaw is 0.5 mm or 0.02 inches, based on holding shop calipers against it. Note the bright orange red color. It’s hard to see in this image, but moving around makes it look glossy, unlike rust. The flaw is somewhat less deep than it is wide.
Well, then, it’s a healing sphere. But if you look at my photo, I can attest that the ball bearing and the “zinc cannonball” are also healing spheres. For that matter there’s a healing Swiss Army Knife and also the top of my healing maple block shop table, and reflections of my healing shop lights, all in that photo.
I accept that it is a healing sphere; the point is I want to know what kind of healing sphere it is.
Looks like a haemetite sphere with a surface coating of lacquer or similar. The orange would be where the coating is cracked and oxyhydroxides have formed.
The mystery sphere has a mass of 0.550 kg, and a density of 2029 kg/m^3. That’s lower than almost all metals and approximately comparable with brick, concrete, silica, or glass. This is well within the typical range of ceramics.
Hematite is more than twice this dense.
I filed down into one of the surface flaws further, maybe a mm. All I got was more of the light tan. There are 3 distinct layers: lustrous hematite looking surface layer, a rich brown layer, and then light pinkish tan. The layers are thin, less than 1 mm, though I don’t know how far the light pinkish tan would go. The entire interior might be that.
Did I say bouncing? I mean, it is a baby, so maybe like a bouncing baby as they say, but you’re not really supposed to bounce babies and they don’t actually bounce all that well anyway as my little brother can attest to.
