Stones, incl. gemstones, are perty pedestrian, chemically speaking.
I remember seeing the formulas for various gemstones in Erf Science, and
feeling quite deflated, a little cheated, by the mundanity of them all.
SiO2, Al2O3, peppered w/ various metal ions, such as potassium, sodium,
beryllium, boron, etc. And, apparently, iron.
Ultimately super-expensive glass and grinding wheels, w/ impurities!!!

And in the case of diamond, just goddamm Carbon!! And thermodynamically
*unstable* C, at that!!
Altho, the various colored diamonds must have another metal stuck somewhere
in the crystal lattice, which probably reduces the hardness somewhat.

Compared w/ organic molecules, such as chlorophyll, the porphyrin ring in
hemoglobin, vit B12, and other structures, stones are perty plain.

Nickel is weakly magnetic, as well. Also liquid oxygen, and a cupla other
things. Someone mentioned Bn? What's dat??

As far as metal in the granite base, I don't believe there is any, as I
cain't see any and the magnet sticks uniformly over the whole surface.
Metal would likely produce local attractions.

You can detect the magnetic properties w/ a good telescoping pickup wand,
but not as nice as with one of those hard drive mags. Need a high mag
strength/weight ratio to really see the effect.

Could be that magnetic granite is crappy granite. Chinese base,
donchaknow...

But at any rate, it will be an interesting past-time to see what rocks are
magnetic around here!
--
Mr. P.V.'d
formerly Droll Troll
"David Billington" wrote in message
...
It would be interesting to know what granite was used for the base of your
height gauge. The black granite I have about shows no magnetic attraction
at all when NiFeBn magnet is placed on it. As granite is predominantly
SiO2 it would be interesting to know why the magnetic attraction .

Proctologically Violated©® wrote:

Awl--

Wouldna bleeved had I not seed it.

Friend brought over a magnet from a hard drive (really nice strong
magnet), and BAM, stuck right to the granite base of my height gauge!
Well, actually, it's just the granite base, cuz there is no height
gauge--supplier's scrap heap, donchaknow....
And stuck perty good! wow....

Thus, boyzngerlz, thar must be iron in them thar granite hills!!
--
Mr. P.V.'d
formerly Droll Troll