silver flex on jade plant
Thanks for your question. I'm going to need a picture to help diagnose this. As closeup as you can, plus a picture of the whole plant. Have you watched the specks to see if they're moving, as in insect? Or do they stay in the same place, like a fungus? I'll wait for photos.
Thanks for the photos! Your plant looks healthy, generally, and you have it in a place it can get adequate light, it appears.
Here are the possibilities: (1) powdery mildew, and here's a link about how to treat that;
(2) an insect infestation, and here's a link about those suspects; or
(3) mineral salt deposits that have come from either the water used for watering them or or from the soil mix used that you have them potted up in. The mineral white chalky looking salts have been excreted via the pores of the fleshy leaves, giving a rather attractive looking spotty appearance to the plant. You can either leave these alone or they can be easily wiped off with a damp cloth with a bit of soapy water.
You're going to have to do some more sleuthing, because any of these require more information that I can get from the photos. (I don't know how 'hard'--mineral laden--your water is, for example. If you can't find any of the other symptoms described for an insect infestation, I suggest you take the conservative approach, and just wipe off leaves with soapy water or neem oil on a q-tip, and see if it comes back.
Hope this is helpful. Good luck!