City of Los Angeles Methane Mitigation Standards The City of Los Angeles Methane Mitigation Standards and Plans are a basic tool to help designers prepare a methane mitigation plan for small projects within Methane Zones. However, the standard plans alone aren’t enough to pass for a proper mitigation plan. For example, the standards lack material…
What is Common Opal? Common Opal is a specific type of opal that usually exists in one color, and has no play-of-color when flashed with light. Unlike precious opal, common opal appears to be “glassy” with transparent and translucent properties. A common blue opal or fire opal gemstone will predominantly reflect one pigment of color from any…
What is Precious Opal? Precious opal is any type of natural opal gemstone that shows a “play of color,” such as flakes of variable colors reflecting from inside the specimen upon white light exposure. Unlike common opal, a precious stone can reflect multiple colors from a single viewpoint. For an example of an opal stone…
Twinning Definition Twinning is the observed intergrowth of multiple crystals in a symmetrical fashion. This term applies to the examination of rock thin sections, in the field of optical mineralogy.
Type Section Geologic Definition In geology, the term “type section” refers to a specific stratigraphic unit, that can be compared to other parts of the geologic unit. For a type section, it’s preferred to describe the location where the geologic unit has the maximum thickness, and where the top and bottom units are observable.
