Pikes Peak Pebble Pups

Pikes Peak Pebble Pups

Sunday, September 21, 2014

Quick Notes on Amethyst

By Steven Marquez

Amethyst is the violet to purple variety of quartz.  Amethyst is often associated with albite and orthoclase in pegmatites. Fine specimens of amethyst can be classified as semiprecious gemstones.

This specimen was found in Cripple Creek Colorado as a near surface deposit on the David Leighton gold mine, owned by Steven Wade Veatch across from the hardware and grocery store on Teller County 1.  The short, stubby amethyst crystals formed gas pockets in a hot, welded ash deposit that once covered the landscape of Cripple Creek. Amethyst is mined in great quantities from the state of Minas Gerais in Brazil.  A deep purple amethyst is commonly found in Uruguay.

The color purple is a royal color which is why amethyst is often used in jewelry for kings and queens. Amethyst was highly valued by Egyptians. The ancient Greeks believed that amethyst was a protector against intoxication.  Amethyst is the birthstone for February. 

Figure 1. A stubby, pyramidal amethyst crystal from a gold mine in Cripple Creek.
Specimen is from the Steven Veatch collection.Photo © by Steven Marquez.

Figure 2. Note the faint crosswise striations on the surface of the amethyst crystal.
This is one of the diagnostic features of quartz. Specimen is from the Steven Veatch collection.
 Photo © by Steven Marquez.

Chemical formula: SiO2
Composition: silicon dioxide; the color is caused by iron or manganese impurities
Color: purple, greasy luster
Streak: white
Hardness: 7
Crystal system: hexagonal
Transparency: transparent to translucent
Specific gravity: 2.65
Luster: vitreous
Cleavage: none
Fracture: conchoidal
Tenacity: brittle
Group: silicates, tectosilicates

Haiku: (a poem by Steven Marquez)
Brilliant purple
Never ceasing to amaze
Glowing like the stars

About the author: Steven Marquez is an Earth Science Scholar with the Colorado Springs Mineralogical Society. He has volunteered hours working on the mineral collection at the Cripple Creek District Museum. He is in the 8th grade and studies with the Pikes Peak Pebble Pups and Earth Science Scholars.

Welcome! This is the gateway to adventure and discovery

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.