Three examples of Calcite in fossil clam 

Rucks Pit, Fort Drum, Okeechobee County, Florida, United States

(Source: lehighminerals.com)

Calcite with Hematite 

Egremont, West Cumberland Iron Field, Cumbria, England, UK 

(Source: irocks.com)

Hematite, Andradite, and Calcite

N’Chwaning Mines, Kuruman, Kalahari manganese fields, Northern Cape Province, South Africa 

(Source: ebay.com)

Duftite on Calcite

Tsumeb Mine, Tsumeb, Namibia

(Source: mineralauctions.com)

Vanadinite with Calcite

Pure Potential Mine, Trigo Mts, La Paz Co., Arizona, USA  

(Source: auction.danweinrich.com)

Galena with Calcite crystals on Chert matrix

Ballard Mine, Bazter Springs, Picher Field, Tri-State District, Cherokee County, Kansas

(Source: exceptionalminerals.com)

earthshaped:

Stibnite, barite, calcite

Dahegou mine, Lushi, Sanmenxia, Henan, China

Galena with Fluorite, Calcite, Quartz

Weardale, Co. Durham, England, UK

(Source: danweinrich.com)