Pikes Peak Pebble Pups

Pikes Peak Pebble Pups

Thursday, November 8, 2012

Park County Tax Sale Lots Yield a Treasure Trove of Chalcedony, Petrified Wood, and Other Specimens

Luke Sattler
Colorado Springs Mineralogical Society Junior Member
Earth Science Scholar Program

I recently took a field trip to the Hartsel and South Park area of Colorado with my brother, grandparents, Steven Veatch (the Pikes Peak Pebble Pups Leader), and his wife Shelly to check on two pieces of real property Steven Veatch received by paying the back taxes through the Park County Treasurer’s Office in Fairplay.

            My grandmother, within seconds, found some beautiful blue chalcedony and some large, very smooth, jet black nodules that may be chalcedony as well. Other colors of chalcedony were found as well as petrified wood. Chalcedony is a cryptocrystalline form of silica, its chemical structure or composition is SiO2 or (silicon dioxide).

Chalcedony forms in lower temperature solutions unlike crystalline quartz, which forms in high temperature solutions (Ralph & Chau, 1993-2012). Chalcedony’s luster is dull to waxy, the hardness of chalcedony is 6 to 7, and has a fracture of uneven to conchoidal. The streak of chalcedony is white. There are many forms of chalcedony that include: carnelian, chrysoprase (green chalcedony), heliotrope (bloodstone), onyx, agate and moss agate.

The specimens of chalcedony, some with agate banding, are from a site near Hartsel in the South Park Ranches Subdivision. The material at this site occurred in veins and over time weathered  free from the vein for easy collecting. This sort of material is called “float” (Figure 1). 
Figure 1. An assortment of chalcedony specimens from the
collection site. Photo October, 2012 by© Luke Sattler .
A Luke Sattler specimen.
Chalcedony at this site also formed  a crystalline habit known as botryoidal. Botryodial’s name refers to its Greek name meaning "grape-like." The grape formation occurs when thick mineral fluids form around a particle into a “jelly” like substance inside a void and solidifyleaving a bubbly looking surface on of the specimen (Smigle, 2012 ). Some of the material formed small vugs or cavities in it from which small drusy quartz crystals grew to form small very attractive geodes (Figure 2).
Figure 2. Image of one of the chalcedony specimens found near Hartsel, Colorado.
Photo October, 2012 by© Luke Sattler . A Luke Sattler specimen.
Exploring the property obtained through the tax sale process not only yielded a great afternoon and fantastic views but provided us a great collecting opportunity where we found within hours various kinds of chalcedony and even some beautiful petrified wood.

References Cited

Ralph, J., & Chau, I. (1993-2012). Chalcedony . Retrieved from http://www.mindat.org/min-960.html

Smigle, B. (2012 ). Botryoidal gems . Retrieved from http://www.bwsmigel.info/GEOL.115.ESSAYS/Gemology.Botryoidal.html


About the author:

Luke is an avid rock, mineral, and fossil collector. He is a member of the Colorado Springs Mineralogical Society and participates in the youth division.  He has written a number of papers on the geosciences and has been published throughout the nation. He is in 9th grade and lives in Castle Rock, Colorado.


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Through this blog pebble pups and junior members of the Colorado Springs Mineralogical Society can access their lessons, work on assignments and projects, and receive details about field trips in the Pikes Peak Region. This Internet program is also suitable for young people who are interested in Earth science but do not live near a rock club or gem and mineral society or for young people anywhere who want a deeper dive into these topics. The only requirement is that all participants must be members of the Colorado Springs Mineralogical Society and must fill out the CSMS membership form (under important websites) and send their registration and membership fee in. Steven Veatch is the senior instructor and will need an email from you with your name, address, phone number, and permission from your parents to participate in this program.