Castle Rock's durability is because of this precious gem

As other rock formations erode and cease to exist, the town of Castle Rock's namesake has kept its shape. What's up with that?

Related Keywords

Castle Rock ,Colorado ,United States ,Castlewood ,Sawatch Range ,Denver ,Mark Longman ,Tim Kathryn Ryan ,Denver Museum Of Nature Science ,Museum Research Associate Dr ,Denver Museum ,Castlewood Canyon State Park ,Kathryn Ryan Curator ,Research Associate ,Buena Vista ,Castlewood Canyon State ,Rock Formation ,