Group of calcite (Calcium Carbonate) specimens, in varying crystal forms, all from Mississippi Valley Type deposits, probably from the Southeast Missouri Lead District around Fredericktown (where this collector was known to have visited). Three large (>4-inch) specimens with calcite crystals on sphalerite-galena matrix, three large (>4-inch) solitary dogtooth calcites, and about eight small calcite specimens (4-to-1.5-inches) in varying forms and with or without other minerals. The calcite crystals in this lot are in two primary forms: nailhead (hexagonal barrels terminated with three blunt faces) and dogtooth (pointy, six-facet cone-like crystals). There are some doubly-terminated hybrids of these two forms as well. See photo for form and condition details.Date: Country (if not USA): State: MissouriCity: Provenance: William Mayrsohn Collection