We use the following substrates: borosilicate glass, Schott Supremax
33, Fused quartz and sometimes old school Pyrex. All of our substrates are free edge chips or"clam Shells".
After diamond generation, fine grinding, polishing, and figuring, each
 optic undergoes several hours of testing and figure touch up.
 We use not one, but several optical tests during fabrication.
 The results from each test are cross-checked against each other in
 order to provide an accurate representation of the optical quality.
 Our testing methods include.
 *Foucault-Null Test (we do not offer Foucault data reduction reports).
*Ronchi-Null Test 
 *Figure of Revolution Test
 *Interferometric Test (if you are a "numbers" guy, this might not be for you.) Our data is composed with several hundred points of data, the numbers are not going to match Foucault data reduction, it's just the way it is. I offer the interferometric data pages as a courtesy, this is done after all other testing has been completed.
 Test Data Provided when requested and/or if supplied as contracted.
Test data reports generally contain the following information:
There might additional charges that apply.
                        Interferogram
                        Strehl Ratio (primary optics and optical systems)
                        RMS Wave front Error
                        Peak to Valley Wave front Error
                        Wave front Map