I purchased some strands of chunky unpolished lapis beads about 5
years ago at the Tucson Gem and Mineral Show. It was a rich blue
color with streaks of gold in it. Magnificent stuff!
Now, it looks like it is drying out and getting a chalky look to it.
I saw some similar material in a necklace where the lapis looked rich
again and oiled(?).
What would be safe to put on this poreous lapis to return it to the
rich blue color that it was before. I am really concerned about it
not getting chalky again.