Id Identification Type Name Description Distinguishing Features Tags
42 Mineral Serpentine minerals A group of hydrous silicate minerals including the fibrous (asbestiform) mineral chrysotile and related members of the kaolinite-serpentine group, occurring primarily through metamorphic alteration of ultramafic rocks.
97 Mineral Siderite Transparent pale green to orange-brown. Nonpleochroic. High-order birefringence. Moderate relief.

Form is somewhat diverse, due to varying means of formation. Common forms are elongate laths with squared off ends and parallel sides (easily distinguished from rice grain shaped aragonite and more rhombic calcite), twinned "bowtie" shapes of multiple laths, or granular rounded euhedra.

Requiring reduced iron, siderite, FeCO3, usually forms deep in the water column, when anoxic bottom waters mix with carbonate-rich surface waters, or diagenetically. Massive amounts of siderite may be precipitated rapidly, and may or may not be cemented with siderite or other phases.
151 Contaminant Slide Glass Slide manufacturing and handling can sometimes produce fine shards that mimic volcanic glass. Pre-cleaning of new slides prior to smear slide preparation can help minimize encounters with this confusing artifact. isotropic conchoidal-fracture contaminant
73 Mineral Sulfur Diagenetic elemental sulfur occurs rarely as yellow nodular masses in sulfate-rich, iron-poor lake systems with active sulfate-reducing microbial communities.

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