Warra wrote:
I took apart an old 120MB disk drive to get the magnet.

I rather like the platters and want to keep them in my house. Maybe
to use as coffee mug mats or something like that.

But I don't want to rest my sandwiches on a platter while having a
coffee and then find that the platters have some toxic coating or can
be a hazard!

Can anyone tell me.

It's probably safe as it's simply a magnetic coating on the disk, but
that shiny surface won't stay shiny for long. Those fingerprints of
yours will be there forever making it look dirty. You could spray the
disk with a clear coating, but is it really worth the effort?

Also, I guess the magnet is made of a special alloy using rare
metals. Could it too be toxic or hazardous?

The hard drive magnets are great fun. I use them for all sorts of
applications. Here's a little shamelessly ripped info:

However, caution must be taken when using neodymium magnets. Even a
small neodymium magnet is powerful enough to destroy the contents of a
floppy disc to such an extent that the information is unrecoverable, a
guarantee not present with techniques such as formatting the disk.
NdFeB magnets are often strong enough to not only magnetize color CRT
shadow masks, but also physically deform the mask itself. Such damage
is typically irreparable by degaussing.

Neodymium magnets should always be handled carefully. Some of the
neodymium magnets that are slightly larger than the size of a penny are
powerful enough to lift over 10 kilograms [1]. They are hazardous,
being able to pinch skin or fingers when suddenly attracted to a
magnetic object. Because they are made with special powders and
coatings, the magnets are very fragile and break at temperatures over
150 °C, or if allowed to smash together. When they break, the magnets
may break so suddenly that flying pieces may cause eye injury.
Neodymium magnets should also be stored away from electrical
appliances, magnetic (bank) cards and computer monitors, as damage may
be irreparable.

Neodymium metal dust is a combustion and explosion hazard.

Neodymium compounds, like all rare earth metals, are of low to moderate
toxicity; however its toxicity has not been thoroughly investigated.
Neodymium dust and salts are very irritating to the eyes and mucous
membranes, and moderately irritating to skin. Breathing the dust can
cause lung embolisms, and accumulated exposure damages the liver.
Neodymium also acts as an anticoagulant, especially when given
intravenously. {So if you were thinking of shooting it up, don't.}

R