I've traveled around Asia a lot... A few of the bigger, more attractive pieces I've found are on my walls. I have a child's kimono I got at a flea market in Japan hanging over my bed. It's slate gray with a hawk/eagle, some fans, and a pine branch on it. On another wall I have a hand-painted scroll of a dragon in the clouds directly from an artist in China. And on a third wall I have a very wispy-looking painting of the Indian god Ganesha in blues, and a beaded string of Ganesha heads with a bell on the end, both from markets in India. Hanging from one of my lights is a colorful fish made out of bamboo fragments that one of my students in Thailand made and gave to me. I also have a bunch of paintings and prints from Japan, some beautiful hand-dyed Indian bedsheets, silk saris, and loads of other things sitting around, waiting for a time when I have space to display them.

While I love rocks and gems and was raised going rockhounding, I would feel weird decorating with crystals like in the first picture. Cool rocks, but every time I looked at them I'd just just feel like I was sharing my house with some absurd crystal healer. Other than that, I have a few fossils I like to keep around, both ones I found and ones I got as a kid going to rock & gem shows.

This is like a collection of shots from my house. Exactly.

I love the beauty of nature in found objects.....driftwood, coral, shells, minerals, rocks and so on. The surface interest and the contrast with sleek and contemporary manmade objects makes for a very interesting mix.

Here's something I've learnt from painful personal experience - watch how you keep those minerals. Have you ever tried to dust something comprising of hundreds of tiny crystals? Yeahhh. There's a reason I keep them in cases now!

I mostly bring home stones from places I visited, but from Kenya I brought tiny inedible berries that local people use to make jewelry. They are purple and as tough as a rock.

I always hit up consignment and thrift shops on my trips, so I have beautiful plates from England, serving flatware from Paris, and a vase from Austria. I even hauled back an amazing rug from Colorado. I love having useful things with an interesting provenance.

Not having the money to travel to foreign ports all that much, I collect cool stuff at flea markets from other people's travels. You don't have to be using treasures like this strictly to reflect your own memories. You can use items like this simply because you love them, and they reflect your interests and maybe even future travel plans...

And displaying crystals is for their sheer beauty -- if anybody imagined I was into crystal healing, a very brief conversation would DEFINITELY set them straight! I used to imagine someday collecting slabs of quartz and other crystals and making them into a fireplace surround, maybe canted inward slightly so the crystals would reflect the firelight! Still like the idea, although now I face the impracticality a bit more squarely! (As long as t hey are not soluble or have delicate inclusions, you can WASH crystals, by the way, not dust them. But if you want to display them and need to dust them, again if they don't have delicate inclusions, you can do it with an old-fashioned shaving brush -- great for all kinds of little dusting!)

I second the comment on keeping crystals under glass! They can get quite grungy quite fast. I've always if canned air would solve that problem...
I'm likewise partial to rocks. And leaves/seed pods in the fall. I also decorate with nature pictures/drawings. Most of my decorative items have an interesting travel story behind them, actually! Why buy something from Target/Ikea when you could have something unique and important to you?

That should read "I've always wondered if canned air would solve that problem..."

@ReversibleRaincoat: Thank you for phrasing "That should read" instead of "That should say".

While I think crystals and geodes can be beautiful, I'm not a huge on having too many decorations. I do especially like the geode bookend - my mom has a pair as well - I've always loved the combination of form and function. These are surprisingly heavy, so they hold up her heavy cookbooks!