| Id | Identification Type | Name | Description | Distinguishing Features | Tags |
|---|---|---|---|---|---|
| 33 | Mineral | Garnet | Transparent colorless to rose or amber. Isotropic. Very high relief. Equant rounded grains are most common, but may also occur as etched and irregular grains. Cleavage absent. Occurs as smaller grains than other minerals in slide because of garnet's higher density. | Isotropic
Heavy-mineral |
pink brown silicate |
| 174 | Lithofacies | Glacial varves | Lithofacies comprising annually laminated sequences of sand, silt or clay deposited in a glacially-influenced lacustrine (or marine) setting.
Repetitively laminated variations in grain size from sand to clay, representing seasonal variations in glacial melt-water cycles and sediment transport; dropstones may be present if deposited in an ice-contact setting. |
laminated graded rythmite glacial |
|
| 15 | Mineral | Glauconite | Blue green to olive green. Often occurs as sand-sized, rounded pellets. Secondary mineral. | green
|
|
| 159 | Mineral | Greigite | Occurs in microbial biofilms, as disseminated crystallites, and as framboids. Opaque where visible by light microscopy. In reduced sediments, greigite is often considered a metastable phase transitional between highly reactive iron monosulfide (mackinawite) and pyrite. Common in reduced lacustrine sediments. | ||
| 46 | Mineral | Gypsum | Transparent colorless. Nonpleochroic. Low birefringence (about the same as quartz). May occur as thin plates (folia), tabular euhedra, or acicular needles. Low relief. Detrital or authigenic. Frequently associated with pyrite when authigenic. May be twinned. Caution: common precipitate from pore waters of cores as they age in storage. Also, heating slide may cause polysynthetic twinning. | Low-relief
Low-birefringence Tabular Acicular |
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