By
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 solidify—leaving 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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