ISO Large Magnifying Glass

Hey Cube! I've searched all the usual prop houses in the city (Acme, prop haus, etc) for a large handheld magnifying glass and am not able to find anything large enough. Does anyone have a fabricated one laying around or know where I could find something pretty huge? Looking for larger than 6" in diameter, preferably twice that size. Thanks so much! Apologies if this posted twice, I didn't see it go through the first time! Lauren