Hi,

I'm a biologist and I haven't understood how to relate cleavage planes
to atomic structure and unit cell of minerals, in particular of
hornblende. If I display the atomic structure of hornblende with a PC
program, could I predict the cleavage planes?

Moreover, how much is the thickness of an hornblende layer? Could I
predict it from its atomic structure and unit cell?

Thank you very much for your help,
Andrea

andrea_gazze@yahoo.it wrote:
Hi,

I'm a biologist and I haven't understood how to relate cleavage planes
to atomic structure and unit cell of minerals, in particular of
hornblende. If I display the atomic structure of hornblende with a PC
program, could I predict the cleavage planes?

Moreover, how much is the thickness of an hornblende layer? Could I
predict it from its atomic structure and unit cell?

Thank you very much for your help,
Andrea

Think about how cellulose fiber in wood cells makes wood have a linear
grain. That linear grain influences why grass and trees grow in lines,
not in circles, though they may have a circular cross-section.

Now, think about you can split wood along fibers but it may be very
tough to chop it across the grain. That's the same thing as cleavage.
"Going with the grain."

The angles of chemical compounds found in minerals cause the mineral to
grow in certain shapes called crystals. Those crystals only interlock in
certain angles. Think about a honeybee hive. Honeybee cells usually have
6 sides. Put a lot of 6 sided cells together in a comb, and you won't
get a comb one cell wide and 200 meters long. It will be compact.


Shapes of crystals are dependent on the atomic structure of the mineral
making it up. When you stack a lot of crystals together, some sides will
not be as tightly joined as others--space will be left. A simple example
is mica. Mica is formed of thin crystal plates stacked atop each other.
It is easier to split mica along the grain (between the plates) than
across the plates.

Now, take that info, and apply it to what you know/can find out about
the structure of hornblende and the interlocking chemical compounds
which make it up.

Jo Schaper wrote:


Now, take that info, and apply it to what you know/can find out about
the structure of hornblende and the interlocking chemical compounds
which make it up.

?? You forgot to mention, .. knit one, purl two... ?

don findlay wrote:

Jo Schaper wrote:


Now, take that info, and apply it to what you know/can find out about
the structure of hornblende and the interlocking chemical compounds
which make it up.

?? You forgot to mention, .. knit one, purl two... ?

I've got a good pattern for knit house slippers if you want it, Don.

K9P2K18P2K9 for 27 rows, thenK2P2for 40 iterations, and turn. Continue
until long enough to reach from instep to toe, usually about 40 rows.
Cut off yarn at 3 ft (.3meter)thread through stitches,tighten to a
circle and use remaining yarn to sew up the top. For women's size 6
foot. Adjust heel pattern in multiples of 1:2:1 if needed for larger
feet, or you can use a 1:1.5:1 pattern and have a cuff on the heel
portion. Increase or decrease K2P2 section as needed; the pattern should
change at the instep of the person for whom the slippers are intended.

Happy Knitting!!