You best bet for appraisal is to send them to an internationally recognized Gemologist. Send registered post and insured. Looks to me like it has some inclusions, good indication it is a natural stone. What does it do under UV light? A natural stone will fluoresces slight to moderately. Other thing to test for is treatments, is it lead glass filled? It will give off a blue flash at particular angles if it is treated but can be hard to spot.