Tool for Microscopic Identification Home



Id Identification Type Name Description Distinguishing Features Tags
61 Lithofacies Tephra Tephra, or volcanic ash, is a mixture of volcanic glass and crystalline grains derived from the same volcanic source. A tephra unit in a core may be predominantly crystalline and coarse-grained at the base, grading upwards to finer, more glassy grains. See volcanic glass for a detailed description and identification; crystalline components can be identified based on their optical mineralogical characteristics. isotropic volcanic-glass
172 Lithofacies Tephra - Glacier Peak G
179 Lithofacies Tephra - mafic
177 Lithofacies Tephra - Mount Saint Helens
173 Lithofacies Tephra - Mt. St. Helens J
176 Lithofacies Tephra- Mazama
185 Mineral Titanite
118 Contaminant Toothpick Small fibers from wooden toothpicks used to disperse sediment on smear slides can be confused with muscovite. Transparent, colorless. Strong second-order birefringence. Shredded or stringy texture common. Low relief. Cellular structure may be visible and can be used to distinguish toothpick from muscovite Shredded
71 Mineral Tourmaline Transparent, variety of colors or colorless. Pleochroic (variable with composition). Moderate birefringence giving vivid colors. Elongate prismatic crystals to rounded grains. Moderate to high relief. Straight extinction. Often has inclusions. Prismatic
112 Mineral Trona Colorless (sometimes cloudy), prismatic or acicular, moderately high relief and high birefringence; may be striated parallel to long dimension. Trona is an evaporite mineral formed in hypersaline lakes or as an efflorescent precipitate on sediment surfaces. Highly soluble in water, and will dissolve and re-precipitate during smear slide manufacturing if water is used; slides should be made using ethanol if the presence of evaporate minerals is suspected. High birefringence; striations; monoclinic habit; solubility in water
171 Lithofacies Turbidite
165 Lithofacies Turbidite sequence