Diamonds and rubies can be filled with a glass-like substance that improves the clarity. Diamond filling goes under the name of its developer "Yehuda" and under trade names such as "Oved". During the last decade a huge amount of rubies particularly from Madagascar have been filled by a similar process. Identifying these stones is difficult for the novice and jeweler alike. For the novice idenyifying diamond clarity enhancement is not possible, refer to your sales reciept as this treatment must be disclosed in both ruby and diamond if purchased from a reliable source. The rubies are slightly easier using magnification as you will see a spider webbing of hairline surface cracks. Most are semi transparent and large stones are purchased for relatively low prices. if you purchased a nice 3 carat plus ruby for $500 or less you likely have a clarity enhanced ruby. These fillings are done on all ruby sizes and may be present in all types of jewelry. There are two types of fracture filling in rubies and these warnings only apply to the lead type glass fillings. The amount of enhanced rubies on the market is great and if in doubt check with a qualified jeweler. It is important that you tell your jeweler of any known treatments if you are having repair work done as these fillings can be damaged by heat, long term ultrasonic cleaning and ammonia. Many home cleaning products containing ammonia can also damage the fillings including, window cleaners, floor polishing waxes, drain cleaners, oven cleaners, toilet cleaners, stainless steel cleaners, bathroom cleaners, multi-surface cleaners and of coarse straight ammonia used as a general cleaner.