I have a several hand carved wood bangles I purchased while overseas. These traditional bangles are carved with rich yet understated designs. I purchased a wood inlay pendant from a local artisan a few months ago. The wood, called blue pine and featuring a faint blue tinge, is polished until it glows like stone and is set into a silver pendant fitting. The artist brought out the wood grain in such a way that the natural beauty truly shines through.
Wood jewelry shouldn't be exposed to water. Water raises the grain and can cause the wood to rot or discolor. If you must clean it due to grime or soil, use a damp cloth and dry it promptly.
Wood also dulls unless it is sealed in a protective finish. My inlay necklace is finished, so I can wipe it clean without fear of damaging it. My bangles, on the other hand, aren't and instead are only lightly stained. I rub beeswax polish into them on occasion. The polish brings out the luster of the wood and provides some protection. The beeswax also hydrates the wood so bangles don't dry out and crack.
With proper care, these pieces are just as durable and timeless as my more traditional jewelry items.