Kentucky State Rock, Mineral & Gem: Coal, Calcite, Kentucky agate

Kentucky's official rock is coal, adopted in 2024. Kentucky's official mineral is calcite, adopted in 2024. Kentucky's official gemstone is Kentucky agate, adopted in 2024.

Symbol names and dates are taken from primary state sources linked below. Informal or proposed symbols are not listed unless adopted.

Coal specimen — Coal (not necessarily from Kentucky). Photo: Amcyrus2012, CC BY 4.0, via Wikimedia Commons

Official rock: Coal

Adopted:: 2024
Law:: KRS 2.091, as amended by Acts 2024, ch. 32 (HB 378)

Coal is a sedimentary rock with a Mohs hardness of about 2–3 and a dull to submetallic luster, usually black or brown.

Coal was Kentucky's state mineral until 2024, when the same act made it the state rock and named calcite the mineral.

How to identify coal →

Often confused with: Anthracite, Cannel Coal, Jet

Also an official symbol of: Utah, West Virginia

Calcite specimen — Calcite (not necessarily from Kentucky). Photo: Robert M. Lavinsky, CC BY-SA 3.0, via Wikimedia Commons

Official mineral: Calcite

Adopted:: 2024
Law:: KRS 2.094, as amended by Acts 2024, ch. 32 (HB 378)

Calcite is a mineral (CaCO₃) with a Mohs hardness of 3 and a vitreous luster, usually colorless, white, orange, yellow, blue or green.

How to identify calcite →

Often confused with: Anhydrite, Apophyllite, Aragonite

Also an official symbol of: Utah

Agate specimen — Agate (not necessarily from Kentucky). Photo: James St. John, CC BY 2.0, via Wikimedia Commons

Official gemstone: Kentucky agate

Adopted:: 2024
Law:: KRS 2.092, as amended by Acts 2024, ch. 32 (HB 378)
Variety:: Kentucky agate

It is a variety of agate. Agate is a mineral (SiO₂) with a Mohs hardness of 6.5–7 and a waxy to vitreous luster, usually red, orange, white, gray, brown or blue.

Kentucky agate was the state rock before 2024; the act moved it to gemstone, replacing the fresh-water pearl.

How to identify agate →

Often confused with: Blue Lace Agate, Carnelian, Chalcedony

Also an official symbol of: Louisiana, Maryland, Minnesota, Montana, Nebraska, South Dakota, Tennessee

Kentucky state symbols FAQ

What is the official rock of Kentucky?

Kentucky's official rock is coal, adopted in 2024 (KRS 2.091, as amended by Acts 2024, ch. 32 (HB 378)).

What is the official mineral of Kentucky?

Kentucky's official mineral is calcite, adopted in 2024 (KRS 2.094, as amended by Acts 2024, ch. 32 (HB 378)).

What is the official gemstone of Kentucky?

Kentucky's official gemstone is Kentucky agate, adopted in 2024 (KRS 2.092, as amended by Acts 2024, ch. 32 (HB 378)).

Did Kentucky change its state rock?

Yes. A 2024 act (HB 378) made coal the state rock, calcite the state mineral and Kentucky agate the state gemstone. Before it, Kentucky agate was the state rock, coal the state mineral and the fresh-water pearl the state gemstone.

Sources

We cite primary sources (statutes, state government pages, federal regulations, and land-manager sites). Third-party listicles are not used as citations.

Kentucky Acts 2024, chapter 32 (HB 378), relating to state symbols — Kentucky General Assembly (accessed 2026-10-24).

Last verified 2026-10-24. Corrections welcome: if a statute has changed, tell us and we'll re-verify.

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