ure are called 'micas;' thus we
have Uran-mica, which is the green leaf I showed you; and Copper-mica,
which is another like it, made chiefly of copper; and this foliated iron
is called 'micaceous iron.' You have then these two great orders,
Needle-crystals, made (probably) of grains in rows; and Leaf-crystals,
made (probably) of needles interwoven; now, lastly, there are crystals
of a third order, in heaps, or knots, or masses, which may be made,
either of leaves laid one upon another, or of needles bound like Roman
fasces; and mica itself, when it is well crystallised, puts itself into
such masses, as if to show us how others are made. Here is a brown
six-sided crystal, quite as beautifully chiselled at the sides as any
castle tower; but you see it is entirely built of folia of mica, one
laid above another, which break away the moment I touch the edge with my
knife. Now, here is another hexagonal tower, of just the same size and
colour, which I want you to compare with the mica carefully; but as I
cannot wait for you to do it just now, I must tell you quickly what main
differences to look for. First, you will feel it is far heavier than the
mica. Then, though its surface looks quite micaceous in the folia of it,
when you try them with the knife, you will find you cannot break them
away----

KATHLEEN. May I try?

L. Yes, you mistrusting Katie. Here's my strong knife for you.
(_Experimental pause._ KATHLEEN, _doing her best._) You'll have that
knife shutting on your finger presently, Kate; and I don't know a girl
who would like less to have her hand tied up for a week.

KATHLEEN (_who also does not like to be beaten--giving up the knife
despondently_). What _can_ the nasty hard thing be?

L. It is nothing but indurated clay, Kate: very hard set certainly, yet
not so hard as it might be. If it were thoroughly well crystallised, you
would see none of those micaceous fractures; and the stone would be
quite red and clear, all through.

KATHLEEN. Oh, cannot you show us one?

L. Egypt can, if you ask her; she has a beautiful one in the clasp of
her favourite bracelet.

KATHLEEN. Why, that's a ruby!

L. Well, so is that thing you've been scratching at.

KATHLEEN. My goodness!

(_Takes up the stone again, very delicately; and drops it.
General consternation._)

L. Never mind, Katie; you might drop it from the top of the house, and
do it no harm. But though you really are a very good girl, and as
good-na