calcite

noun

cal·​cite ˈkal-ˌsīt 

: a mineral CaCO₃ consisting of calcium carbonate crystallized in hexagonal form and including common limestone, chalk, and marble compare aragonite

calcitic

kal-ˈsi-tik 

adjective

Examples of calcite in a Sentence

Recent Examples on the Web

Using x-ray fluorescence spectrometry, scholars determined that the ancient off-white fluid was composed of calcite, huntite, and miniscule flecks of yellow orpiment, a highly toxic sulfide of arsenic that Egyptians also used in medicine to treat syphilis and malaria. —News Desk, Artforum, 9 Mar. 2026

Geologists concluded that the boulders formed over four million years as calcite built up around an organic core, which also caused the rocks' striking cracks to form over time. —Madeline Bilis, Travel + Leisure, 8 Mar. 2026

These little ocean critters belong to a family of phytoplankton whose main talent lies in converting dissolved carbon into calcite. —Ben Mather, Space.com, 7 Feb. 2026

For context, Limestone, which also contains calcite, has a 2 or 3 hardness rating. —Barbara Bellesi Zito, Southern Living, 2 Jan. 2026

Word History

First Known Use

1840, in the meaning defined above

Rhymes for calcite

• affright
• airtight
• albite
• alight
• alright
• aplite
• aright
• bainite
• birthright
• bobwhite
• bornite
• bullfight

Kids Definition

calcite

noun

cal·​cite ˈkal-ˌsīt 

: a mineral substance made up of calcium carbonate and found in numerous forms including limestone, chalk, and marble

calcitic

kal-ˈsit-ik 

adjective

Medical Definition

calcite

noun

cal·​cite ˈkal-ˌsīt 

: a mineral CaCO₃ consisting of calcium carbonate crystallized in hexagonal form and including common limestone, chalk, and marble

calcitic

kal-ˈsit-ik 

adjective