Yule marble shear strength through "bedding Plane"

[abknight@zzzzzz]

I was having a conversation with a list member on the subject of bedding
plane in marble I am bringing before all because I have lost my
correspondents address and perhaps the geo-informed can might wish to emante
mighty light.

The Yule marble has a tendency to shear along what is spoken of as the
bedding plane of the stone.  Other marbles, most famously, the Carrara have
very little or no shear orientation.  I understand the bedding plane to be
the dimensional orientation of the depositional surface, probably more or
less horizontal at the time of deposition.

As Formifera plankton die, their calcareous corpses snow down into the
shallower depths of the seas (as the material dissolves in greater depths
this limit is called the snowline by geologists).  They pile up at the rate
of up to a couple of centimeters a 1000 years and eventually form limestone
when the pressures of their own weight compact them and create
concentrations of chemical high enough to grow calcite crystals which infill
any open areas and then go on to convert all of the shell matter into
complete crystal form.  I don't have the book on marble formation and this
is wear my information runs out.

As for the shearability of certain marbles, which seems to follow the same
dimensional orientation as the depositional bedding plane, I really don't
know why.  In many marbles such as the Yule the crystals seem to form better
adhesion across this plane than they do through the vertical column.  That
is mysterious and I would like to understand that better.

Perhaps something happens in the metamorphic transition, for I guess at
that time the limestone crystals dislove and recrystalize.  It would seem
this strenth of grain would be established at the time of crystal growth.

I think of limestone as a very well consolidated material through all
dimensions, but perhaps there are many limestones less well vertically
consolidated that I do not know of. Perhaps it is one such as that from
which the Yule is metamorphosed.

Certainly, in the case of the Yule the figuration or coloring of the marble
runs through this same planar orientation.  But figuration also has a more
cloudy characteristic that is less dimensionally oriented. Does the color
come from mineral invasion of seams of less dense material during
metamorphosis or is the colored mineral already present at the time of
metamorphosis, perhaps introduced during initial deposition.   All simple
questions for a good encyclopedia.  How many vertical inches of limestone to
make an inch of Marble, O Great Internet?  It's all probably in a learning
stone archive....Too many questions, time for a nap,   Lazy Bill