Calcite is one of the most common minerals on Earth, occurring in a vast array of crystal habits and colors. It is easily identified by its rhombohedral cleavage, its hardness of 3 on the Mohs scale, and its immediate reaction to dilute hydrochloric acid.
Is this calcite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch calcite with a known reference. Calcite sits at Mohs 3 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Calcite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Calcite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, colorless, yellow, orange, blue, green, brown, pink, red.
- 5Look at form & habitCrystal system: trigonal. Typical habit: rhombohedral, prismatic, scalenohedral, massive, stalactitic.
Often confused with
Calcite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside calcite
Minerals reported to co-occur with calcite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaCO₃
- Mohs hardness
- 3
- Density
- 2.71 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Trigonal
- Crystal habit
- Rhombohedral, Prismatic, Scalenohedral, Massive, Stalactitic
- Cleavage
- Perfect in 3 Directions
- Fluorescence
- Often Fluorescent White, Yellow, Or Pink Under SW and LW UV
- Rarity
- Common
- Uses
- Collector, Decorative, Industrial, Optical
- Host rock
- Sedimentary Limestones, Hydrothermal Veins, And Metamorphic Marbles
- Typical price
- $2-20 thumbnail, $30-200 display specimen
Where rockhounds find calcite
204 mapped spotsClassic worldwide localities
- Mexico
- USA
- Iceland
- China
- Germany
- Morocco
U.S. states with calcite
Each link opens a state-specific list of mapped rockhounding spots that produce calcite.
- Missouri29 spots
- Utah21 spots
- New Jersey13 spots
- Pennsylvania11 spots
- Tennessee10 spots
- West Virginia10 spots
- North Carolina9 spots
- Wisconsin9 spots
Field-hunting tip
Look in sedimentary limestones, hydrothermal veins, and metamorphic marbles country — that is the host setting where calcite typically forms. If you start seeing quartz, fluorite, barite in float, you are in the right ground. Field specimens usually show a rhombohedral, prismatic, scalenohedral, massive, stalactitic habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Missouri, Utah, New Jersey — start trip planning there.
Common questions
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Find calcite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
