Mineral resource classification is the classification of mineral deposits based on their geologic certainty and economic value.
Here's a list of the top 10 most expensive cities in the country, ranked by average monthly rent for a single person: 1. San Francisco, $2,077. 2. New York City, $1,994. 3. Boston, $1,721. 4. Washington, D.C., $1,397. 5. Seattle, $1,288.
Including rent, other U.S. cities among the most expensive included Chicago (7th), Miami (11th) and Los Angeles (13th). The cheapest cities last year among the 71 surveyed: Kiev, Ukraine, and the Bulgarian capital city, Sofia. Prices were 2.5 times higher in the Swiss cities than in those Eastern European capitals.