Refractive indices and birefringence values were obtained with a standard refractometer and a near-monochromatic light source. Specific gravity was determined using a Mettler-Toledo hydrostatic meter. Reactions to ultraviolet radiation were observed using standard long-wave (365 nm) and short-wave (254 nm) lamps. Visible absorption spectra were obtained with a Krüss prism spectroscope. Visual features were observed using an SZM-2 zoom microscope from Gemmarum Lapidator with darkfield illumination at 20×–80× magnification. Inclusions were photographed with an Olympus BX41 microscope using immersion techniques.