When 'fresh from the bath', they look larger because they are brighter. For such small objects, diamonds attract a surprising amount of grease and dirt.

Oils in make-up and lotions coat them
Dust and powder stick to them
Soap dries on the under side

You can soak diamonds in warm suds made with a good detergent ; brush them lightly , top and bottom, with a small-sized toothbrush having soft bristles, and then dip the diamonds in alcohol and dry on tissue; otherwise dry with a soft cloth.

When not wearing your jewelry wrap each item separately in the jewel box. Do not jumble ; diamonds can scratch not only each other, but other stones as well.