It is indeed organic & in true spirit of the Arts & Crafts Movement. The date on your ring is the first part of the 20th century. Craftsman & home hobbiest produced this type of design into the 20''s. The "stone" is a classic A&C stone (again keeping with the organic design) and is refered to as a Blister pearl.
Love it! Wouldn''t do a thing to it. If it gunky clean only the gold with a soft tissue (soft toothbrush for the hard to reach crevices). Less is more & yes, the pearl is soft - I would buff with a tissue.
If you would like to see some other Arts & Crafts jewelry, I posted some pics in the thread on Edwardian Jewelry in the "Diamond Book" section under the heading "Diamond Rings, design, style, techical issues & care.
i really love this ring and think that removing gunk on the gold is one thing but the patina of the years on said gold should be retained.
f&i, the picture of your home posted in the above referenced thread is gorgeous. i can''t imagine being in that room without wearing the appropriate Arts and Crafts jewelry.