Elongate mineral particles in the natural environment

Abstract When considering elongate mineral particles (EMPs) in the natural environment it is important to first: 1) define what an elongate mineral is and 2) present what we as mineralogists and geologists know about their distribution. However, it is often very difficult to define the natural world, instead we physical scientists resort to describing it. For instance, we used 1,419 words spread over two pages of our mineralogy textbook (Dyar and Gunter, 2008) to describe a mineral. On the other hand, elongate has a rather simple non-quantitative definition as a particle longer than it is wide; however, to quantify it, we must select an aspect ratio. Cleary the term EMP was coined with the hopes to simplify some of the confusion resulting in the differing “meanings” of such words as asbestos, asbestiform, acicular, and most importantly “fiber” in the natural vs. built environment, especially when applied to amphiboles (Gunter, 2010), and non-regulated asbestiform amphibole species. This paper draws on three sources: 1) the USDA-NRCS soil database (Thompson et al., 2011), 2) soil mineralogical data from USGS (Smith et al., 2013), and 3) the mineral database created in conjunction with the Dyar and Gunter (2008) textbook in an attempt to show issues created by use of the term EMP.