RocksdayMaryland State Mineral & Gem: Chromite, Patuxent River stone
Maryland's state mineral is chromite, adopted in 2025. Maryland's state gem is Patuxent River stone, adopted in 2004.
Symbol names and dates are taken from primary state sources linked below. Informal or proposed symbols are not listed unless adopted.
State mineral: Chromite
- Adopted:
- 2025
- Law:
- Chapter 487, Acts of 2025
Chromite is a mineral (FeCr₂O₄) with a Mohs hardness of 5.5 and a submetallic luster, usually black.
Often confused with: Magnetite
State gem: Patuxent River stone
- Adopted:
- 2004
- Law:
- Chapter 272, Acts of 2004
- Variety:
- Patuxent River stone
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.
The Maryland Manual describes it as an agate found only in Maryland.
Often confused with: Blue Lace Agate, Carnelian, Chalcedony
Also an official symbol of: Kentucky, Louisiana, Minnesota, Montana, Nebraska, South Dakota, Tennessee
Maryland state symbols FAQ
What is the state mineral of Maryland?
Maryland's state mineral is chromite, adopted in 2025 (Chapter 487, Acts of 2025).
What is the state gem of Maryland?
Maryland's state gem is Patuxent River stone, adopted in 2004 (Chapter 272, Acts of 2004).
Sources
We cite primary sources (statutes, state government pages, federal regulations, and land-manager sites). Third-party listicles are not used as citations.
- Maryland at a Glance: State Mineral — Maryland State Archives (Maryland Manual) (accessed 2026-10-24).
- Maryland at a Glance: State Gem — Maryland State Archives (Maryland Manual) (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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