All jade and stone carvings/sculptures are wiped with beeswax or an oil substance to keep it moist before it is wrapped in a paper towel like packaging for shipping. Retail shops in China usually have small glasses of water inside the cases with their jade sculptures.
Stone does dry out and it is important to have a regular care routine for your sculptures. Just like you would have a humidifier in your home for all of your wood cabinets, trim and furniture to keep it from drying out and becoming brittle. I keep a small glass of water in my curio cabinets. Also, at least once a month, I wipe down my jade & stone sculptures with a furniture polish called Liquid Gold or a natural beewax polish. It enhances the colors in the sculpture and keeps it from drying out. If your B, C and D jade or stone sculpture starts to show signs of dry "spots" before the end of the month, you might want to start wiping it with the Liquid Gold or beeswax more often than once a month.
Do not use Liquid Gold on your white jade sculptures! Liquid Gold will turn your white jade yellow. I use a natural Beeswax polish for my white jade pieces. You might want to test a small section with your oil before applying it to see its reaction.