Answer: Lilies ("Lilium") grow from bulbs composed of overlapping fleshy scales. These bulbs never go completely dormant and do not form a protective tunic unlike tulips or daffodils. Instead the overlapping scales help to ensure the survival of the "heart". Even if outer scales are damaged or broken it will not hurt the interior structures.
A broken scale is capable of asexual reproduction by producing small miniature clones called bulblets. This is the bulb's natural way of ensuring it's survival if damaged. While you can peel away a few of the scales from the outer part and plant them, they won't flower for 2-5 years. It would be best to plant the entire bulb.
The black pebbles might be seeds. The seeds develop inside the embryo of the flower (big puffy seed pods will develop where flower used to be). You can harvest the seeds when the pod turns brown (late fall).
After you have harvested the seed pods, break them open over a piece of paper and you will find many disc like flakes. If you hold the flakes (seeds) up to light only some of them will have something "inside" them. If the flakes are clear (empty) then they are not fertile and should be discarded. Only some seeds (flakes) will be good. If the lily has not been visited by bees at all, none of the flakes may be any good. You will have to try and chance it.
The best way is to put the seeds in a plastic bag (ziplock) of slightly moist seed starting mixture or cactus planting mixture. Leave plastic bag at 65-70F for 4 months keeping it barely moist. Then put in the fridge for 3 month at which time small bulbs develop. Finally bring out and plant the small bulbs 1/4" deep in small pots. Plant outdoors after last chance of frost.
Oriental lilies will not create plants which are true to type (e.g. the offspring will most likely not look like the parent).
Best wishes with your lilies!
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