Rhodochrosite

Abstract
Abstract
The formation and general information of the mineral rhodochrosite are provided as a background for this paper.  Observations and comparisons of its physical and microscopic properties are included and featured in tables and figures.  The use of rhodochrosite as both a catalyst and precursor material for hydrocarbons are examined further.  While isolated, it is observed that rhodochrosite is a poor catalyst.  However, when used as an ingredient for a hydrocarbon catalyst, rhodochrosite is an effective material for the reduction of nitric oxide and nitrogen dioxide pollutants.   


Background

Rhodochrosite is a mineral found in the calcite group with a chemical formula of \(MnCO_3\).  Pure rhodochrosite is relatively rare, however, so the manganese may be partially replaced with calcium, iron, or magnesium (Britannica 2008).  It generally forms in low to moderate temperature ore veins near deposits of copper, zinc, lead, and silver but sometimes can be found in sediments and pegmatites (Harker 2014).
Because it is part of the calcite group, rhodochrosite has a perfect 3 cleavage which helped in my determining of my previously unknown mineral.  Along with cleavage, the distinguishable pale rose pink color is a useful indication of the mineral. When performing a hardness test on the mineral, I noticed that I could not scratch the surface with my fingernail (<2.5 on the Moh's hardness scale) nor could the mineral scratch a piece of glass (5.5).  This left a window from 3-5 in which rhodochrosite fit perfectly with a hardness of 3.5-4. I also found that the unknown mineral had a vitreous luster and a white streak.  After researching, I determined that my unknown mineral was rhodochrosite.  All data and comparisons to the Mineralogical Society of America Mineral Identification Key (Plante et al 2003) are found in Table 1.  
After reviewing the physical properties, I also performed XRD and Raman Spectroscopy tests in order to look more in depth.  Figure 1 and Figure 2 show my data compared to RRUFF database Raman and Powder Diffraction graphs.  The peaks for each match perfectly to what the unknown mineral had thus confirming that my mineral was rhodochrosite. 

My Mineral Web Mineral
Hardness 3-4 3.5-4
Cleavage 3 perfect 3 perfect
Luster vitreous; silky vitreous; pearly
Streak white white
Color pale rose pink; gray pale rose pink; gray; brown-white
Other No HCl reaction; cannot scratch glass
Table 1. My physical property test observations versus the Mineralogical Society of America Mineral Identification Key found on the web.  Miscellaneous details that helped me further determine my unknown mineral are listed under "Other". 
 XRD Powder Diffraction data from RRUFF database shown in blue compared to my own data shown in red.