Featured red coral turning white...need help

I left it alone. Did not end up trying to remove the white powder.
Did not end up displaying it. Frankly I forgot about getting this dome until you revived this post.
Am sorry but through this lock down and the troubles i never ended up doing anything as was suggested by the wonderful group members.

 

Totally understandable. Stay safe.

 

... and left alone, in the Sea where it belongs! The Great Barrier Reef is disappearing at the rate of knots. Much of it is like a barren desert at the bottom of the ocean.

 

One of the many reasons why I only buy vintage and antique jewellery.

That is due to global warming, not coral harvesting. Which doesn't let coral harvesting off the hook, of course.