Dark color is more likely to contribute to overheating in the summer. It can help with heavy mass walls, but won't do much good for an insulated wall. Heat that is produced, will be quickly lost to the cold wind. Dark paint and especially dark shingles, can have a short lifespan, due to overheating.
I found some pretty shells, some sea glass and this lovely tiny ad:
40 things, worth over $600, all for $35 - the permaculture adventure bundle
