| Id | Identification Type | Name | Description | Distinguishing Features | Tags |
|---|---|---|---|---|---|
| 60 | Mineral | Rhodochrosite | Greenish-brown in plane light. Strongly pleochroic. High birefringence. Ellipsoidal; may be difficult to distinguish in smear slide from siderite or dolomite. Forms in environments with reduced Mn. Occurs in lakes and estuaries, but uncommon; rare to absent in marine settings. | Brown-green
High-birefringence |
|
| 120 | Mineral | Rutile | Transparent gray-green. Nonpleochroic. Strong second-order birefringence with vivid colors. High relief.
Usually detrital, but in rare cases may form diagenetically (M. Talbot, pers. comm). May appear as multiple contact twins. |
high-relief transparent twinned heavy-mineral |
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