Colorado

Rocks and specimens from Colorado

How to Become a Museum Curator

In this economy, we all could use some career advice. Here is an interview with a former curator of the Denver Museum of Nature and Science, explaining how he got the job and what it entails. (more…)

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Anthracite

Q: What makes rockhounds different from non-rockhounds?

A: They are happy to receive coal for Christmas.

Rockhounds love coal, and they love anthracite even more. Anthracite is a type of coal. It is very hard and burns slowly and cleanly due to its high carbon content and few impurities. It is rarer than bituminous coal (the soft, most common form of coal); in fact, less than 2% of the coal in the United States is anthracite. Also unlike bituminous coal, anthracite won’t leave soot on your fingers when you touch it.

There are four types of coal in all. The last two we haven’t covered yet are lignite coal and subbituminous coal, which have the lowest carbon content and are even softer then bituminous coal. Anthracite is the hardest and has the highest carbon content. Most of the coal in the United States is found in Colorado and Illinois, and is used primarily for making electricity and coke (coke is used by foundries to make iron and steel).

Christmas Rhodochrosite

A cluster of crystals that has square red crystals on a shiny green surface, with white and lavender puffballs scattered across the whole cluster. A nice display of Christmas colors.

Ex. J. Vorpahl Mineral Collection, http://www.themineralgallery.com/rhodoroom.htm

This gorgeous crystal specimen is perfect for Christmas! It has red rhodochrosite crystals on a green matrix (green pyrite?), with pale lavender fluorite cyrstals that look like little snowdrifts. From Steve’s Pocket, Fluorite Raise, Sweet Home Mine, Alma, Colorado.

Dendritic Agate

Dendritic agate has inclusions that look like thin, two-dimensional tree-like growths.  They are usually black or dark brown, especially if they are found in Montana.  Often dendrites form, between flat “waterline” bands of agate.  Dendrites may also occur in limestone, talc, sandstone, beryl, corundum, and other minerals.  Dendritic and moss agates both look amazing as cabochons, because they look like little pressed flowers or landscape scenes.  The specimen pictured is from Del Norte, Colorado.
Source: The Gemrock, 7/2014

Fossilized Leaves for the First Day of Fall


Happy first day of fall!  Or happy first day of autumn, if you prefer.  To celebrate, here are some great fossil leaves from fossilplants.com.