Precision Optical Laser NATURAL Crystal Quartz Optics Z-Cut 58mm x 53mm x 43mm rough Overall solid condition. All my glass/quartz came from a government lab that was cutting their own crystal for laser optics (and other unknown applications). We have bought lasers from this same lab, many are Coherent and Melles Griot. We will allow you to buy this and examine it with your own lab equipment to ensure this meets your standards. If you don't like it, return it. We trust this product completely. On this particular piece this has a raised window in the back (not sure why) 269 grams / 9.5 ounces 58 x 53 x 43 mm (with a piece cut off one corner - as seen) We are not experts in laser optics, but please ask questions and we will try and answer you the best we can. **Please look at my other quartz lots. I have other optical crystal listings and will be listing many more. if you want a bunch of this, we can work out a deal**** Will ship international. Please look at pictures. I am in military reserves and sometimes get called away for duty. I will ship as soon as I can.