http://www.minerals.net/ – Tons of free informational guide to minerals, crystals and rocks. This website is a great reference site for people interested in geology and is updated regularly.
http://www.agates.eu/ – A handy website with great information about agates.
http://geology.com/ – Get the latest news and happenings in the world of geology and Earth science here.
http://coloreddiamondguide.com/ – Advice for fancy colored diamond shoppers who want to get the best value out of their dollars here.
If you have a related or thematic site and are interested in getting listed here, do drop us an email and get in touch with us.