"ATM" Fused silica properties??

[Vburnham@aol.com]

This past summer I purchased a blank that was advertised as fused silica at a
swap table.  Later a friend who was also at the convention said there was
some discussion as to whether the blanks were indeed fused silica.

It is just under 6” in diameter and was about 2.25 inches thick (I sawed it
into two disks)  all surfaces were well finished and colorless.  (Water clear
inside)

Not knowing what fused silica should look, feel or grind like is there any
simple way to verify what this material is ?  I would hate to spend time
grinding and polishing a mirror out of something not suited to the purpose.

Thank you
Vance Burnham