I assume you want two pieces of about equal thickness ? I would start from scratch with a new blank . If you only need half of what you have there , grind it down .
Scroll saw might work if you make a jig to support it rock solid . Fine tooth Japanese style hand saw might work . One vital (I think) requirement of any saw is that it have a brand new blade , to ensure that the teeth are evenly set . If they aren`t , the blade will wander . Good luck !