Silica Phytolith with Carbon

This is from the La Tuna fire in Los Angeles, California in 2017. This is from an environmental tapelift collected outside a home near the La Tuna Fire. The refractive index of the mounting medium is approximately 1.485 (acrylic adhesive and Shurmount). With this configuration of oblique illumination the particle being bright on the right side indicates that it has a refractive index lower than the mounting medium. Silica phytoliths have a lower refractive index but glass fiber used in homes all have higher refractive indices. The brown color is due to light scatter. With reflected light the particle appears slightly blue due to reflected light scatter.