Asbestos is a generic commercial term given collectively to a group of six fibrous silicate minerals that occur in sufficient quantity and quality to be mined and processed for industrial and commercial applications.  The term “asbestiform” is used to describe the unusual crystallization habit (the actual shape assumed by a crystal or aggregate of crystals) of minerals when the crystals form as thin, hair-like fibers such as that which occurs with the six asbestos minerals.  Naturally occurring asbestos (NOA) is the general all-encompassing name given to asbestos minerals found in-place in their natural state.  The term "NOA" is typically used in situations where the asbestos minerals are found in such low quantities that mining and commercial exploitation are not feasible.  While large commercial deposits of the asbestos minerals are rare, small non-economic occurrences of asbestiform minerals are more common.  Amphibole and serpentine minerals tend to occur in metamorphic, igneous, and ultramafic rock terrains, which are major constituents of approximately 30%-40% of the continental U.S.  Under specific geological conditions, these minerals can form into long, thin fibers that may be classified as asbestos or NOA.  Airborne asbestos may potentially be released from NOA deposits, absent appropriate engineering controls and work practices, and may pose a potential environmental health hazard if these rocks are crushed or exposed to natural weathering and erosion or to human activities that create dust.

In the analysis of substances for the presence of asbestos, it is important from both a scientific and regulatory standpoint to distinguish between asbestiform and non-asbestiform rock fragments (commonly referred to as "cleavage fragments").  Long, thin cleavage fragments, while rare, may resemble asbestos fibers.  The Occupational Safety and Health Administration (OSHA), however, decided in 1992 that cleavage fragments are not asbestos and should not be regulated as asbestos based on epidemiology studies that were either inconclusive or showed no adverse health effects from exposure to non-asbestiform mineral particles.  Through the use of transmission electron microscopy (TEM), scanning electron microscopy (SEM), and optical microscopy techniques, RJLG has the expertise to identify the morphological characteristics of asbestiform and non-asbestiform minerals and characterize the composition of complex mixed mineral dusts.