Re: Yes, there is a Mineral Definition

tabisheer is opal produced inside injured or diseased bamboo.

What about chalcedony?

Carl
1 Lucky Texan


Landy wrote:
> "Carl 1 Lucky Texan" <[EMAIL PROTECTED]> wrote in message
> news:[EMAIL PROTECTED]
>
> > So what is opal?(or even tabisheer?) or obsidian?
>
> Opal is often referred to as a "mineraloid", since it has a restricted
> compositional range but does not have a crystalline structure (it is
> amorphous).  Obsidian (also amorphous), on the other hand can have a huge
> range of compositions, and is therefore a rock -  note if allowed to
> crystallize it would for a felsic igneous rock of some sort (e.g. dacite,
> rhyolite, granite).  And sorry, I've never heard of tabisheer?
> cheers
> Bill
>
>
>
>
>
>
> > Carl
> > 1 Lucky Texan
> >
> >
> > Fred_Miner wrote:
> >
> > > DEFINITION OF A MINERAL:    A mineral is a natural, homogeneous,
> inorganic
>
> > > solid with a crystalline atomic structure. Crystallinity implies that a
> > > mineral has a definite and limited range of composition, and that the
> > > composition is expressible as a chemical formula.
> > >
> > >
> > > > From  http://www.mine-engineer.com/mining/mineral/mineralindx.htm
> > >
> > >
> > > Bob perhaps you could stumble into the library, next time, or are they
> out
>
> > > of fashion now days.
> > > The other day I was wondering, are there parallel dimensions around us,
> or
>
> > > are they just figments of my imagination , , ,
> > >
> > >
> > >
> > >
> > > "Bob" <[EMAIL PROTECTED]> wrote in message
> > > news:[EMAIL PROTECTED]
> > >
> > >
> > > > I am stumbling to find a true definition of a mineral, to help me
> > > > figure out if the following are indeed considered minerals:  A bone -
> > > > A shell from a crustacean, Petrifed wood, a fossil, and Coal.  Can
> > > > anyone help out there - thanks - Bob
> >
> > --
> > to reply, change  ( .not)  to  ( .net)


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