Marcasite - Brushy Creek, Mo
Introduction
The Brushy Creek Mine in Missouri is renowned among mineral enthusiasts and geologists for its exceptional specimens of calcite and marcasite. Nestled in the picturesque Ozark Mountains, this mining site has been a source of fascination and wonder for both collectors and scientists alike. In this article, we will delve into the geological history, formation processes, and the unique beauty of calcite with marcasite from the Brushy Creek Mine.
Geological Context
The Brushy Creek Mine is situated in the Viburnum Trend, a well-known lead-zinc mining district in southeastern Missouri. The Viburnum Trend has been a hub for mineral extraction for over a century, and its significance in the world of geology and mineralogy cannot be overstated. The region's geological history is marked by the presence of ancient seas, sedimentary deposits, and tectonic activity, all of which have contributed to the formation of the remarkable calcite and marcasite specimens found in this mine.
Formation of Calcite and Marcasite
Calcite and marcasite are two distinct minerals, each with its unique properties and characteristics. They often co-occur in mineral deposits like those found in the Brushy Creek Mine. Let's explore the formation processes of these minerals:
Calcite
Calcite is a common mineral composed of calcium carbonate (CaCO3). Its formation in the Brushy Creek Mine can be attributed to a series of geological events. The region was once covered by ancient seas, and over millions of years, the remains of marine organisms, such as shells and coral, accumulated on the seafloor. Under the weight of subsequent sedimentary deposits, these organic materials underwent a chemical transformation, resulting in the formation of calcite crystals. The beautiful calcite specimens found in the Brushy Creek Mine often display a range of colors, from clear and colorless to shades of pink, yellow, and green, due to impurities within the crystal lattice.
Marcasite
Marcasite, on the other hand, is an iron sulfide mineral with a chemical composition of FeS2. It often forms in sedimentary environments rich in organic matter. In the case of the Brushy Creek Mine, marcasite is thought to have formed as a result of the decomposition of organic material, such as plants and microorganisms, in the presence of sulfur-rich water. Over time, these conditions allowed marcasite crystals to grow, creating stunning, brassy to golden metallic lusters on mineral specimens.
Characteristics of Calcite with Marcasite from Brushy Creek Mine
The calcite with marcasite specimens from the Brushy Creek Mine are renowned for their aesthetic appeal and geological significance. These specimens typically feature intricate combinations of translucent to transparent calcite crystals intergrown with the metallic luster of marcasite. The calcite crystals can take on various habits, including scalenohedral, rhombohedral, and dogtooth forms, contributing to the overall beauty and diversity of these mineral assemblages.
One of the most distinctive features of these specimens is their colorful nature. Calcite crystals often display hues of pink, yellow, green, and sometimes even blue, making them visually captivating. The juxtaposition of these vibrant calcite crystals with the glittering marcasite enhances the overall visual appeal of the specimens.
The textures of these specimens vary, from druzy coatings of tiny calcite and marcasite crystals to larger, well-defined crystals that can be several inches in size. This diversity in texture provides collectors and researchers with a wide range of specimens to study and enjoy.
Scientific Significance
Beyond their aesthetic allure, calcite with marcasite specimens from the Brushy Creek Mine holds significant scientific importance. Researchers and geologists have studied these minerals to gain insights into the geological history of the region, as well as to better understand the formation processes of these minerals. Additionally, they serve as indicators of ancient environmental conditions, shedding light on the past climate and geological activity.
Collecting and Conservation
The Brushy Creek Mine is a historically important site for mineral collectors, and it's crucial that these unique specimens are collected responsibly. Many collectors and organizations work closely with mine operators to ensure that the delicate balance between mineral extraction and environmental conservation is maintained. Collectors often use hand tools and practice careful extraction techniques to minimize damage to the specimens and the surrounding geological formations.
It's important to note that the Brushy Creek Mine, like many mineral localities, is situated on private land, and access is typically granted with permission from the landowners. Visitors are encouraged to respect the rules and regulations set by the mine operators and to appreciate the natural beauty and geological wonders of the area while preserving them for future generations.
In Closing
The calcite with marcasite specimens from the Brushy Creek Mine in Missouri are true geological marvels. They offer a window into the ancient history of the region, showcasing the transformative power of geological processes over millions of years. These specimens are not only treasured by collectors for their aesthetic beauty but also serve as valuable tools for scientific research and education.
As we continue to uncover the mysteries of the Earth's geological past, these minerals from the Brushy Creek Mine remain a testament to the enduring allure of the natural world and the ever-evolving field of geology. The story of calcite with marcasite from Brushy Creek Mine is one that continues to captivate and inspire enthusiasts and researchers alike.
From the Andaluz Collection:
A complete calcite cluster from the well-known Brushy Creek Mine
from the famous and still unique pocket of the late 1980s (106 drift, 1100' Level).
The lustrous, white to grey calcite scalenohedrons range up to 3.5 cm.
Far more translucent than you normally find from here, the calcites are instantly
recognizable with their preferential coating of sparkly chalcopyrite and/or marcasite crystals.
The sulfides have good luster and a light iridescence whose colors cover much of the spectrum.
Distinctive, this is classic material for the Brushy Creek mine. It was worked briefly
in the mid-1900s and also in a more recent specimen-mining venture by Joe Kielbaso and
friends in the late 1980s, from which this came. A balanced, perfect miniature from this classic find.
It remains unique today.
Collected by Mark Kielbaso, and later purchased by partner Mike New in 94'
Brushy Creek Mine, Missouri