This page explains where the map data comes from, how each place gets its status, and how often records are checked. It applies to the rockhounding map, the state guides, the mineral pages and the location guides.
Where the data comes from
The map combines two layers. The first is a large reference layer built from public datasets. The second is a smaller, hand-curated core of places where people actually go to collect.
- USGS Mineral Resources Data System (MRDS) and related USGS mineral occurrence data. These historical records, about 597,000 of them, describe mines, prospects and mineral occurrences. They are excellent for research but many are decades old and say nothing about who owns the land today.
- State geological surveys. County geology, bedrock and surficial maps and state mineral resource reports give local context.
- Paleontological records. Published fossil occurrence data helps place fossil-bearing formations.
- Land managers. Bureau of Land Management, U.S. Forest Service, National Park Service, state park and wildlife agencies, counties and cities. Their published rules decide what you may collect.
- Protected area boundaries. Public land boundary data (such as PAD-US) helps show who manages an area.
- Operators. Fee-dig mines, gem mines and private collecting sites publish their own seasons, prices and rules.
- Visitors. Field reports and photos sent through our contact form, checked before they are used.
The four statuses
Every curated place has one status. The status describes the activity the evidence supports, not the geology.
- Ready: a current source from the land manager or operator supports the activity shown (for example, hobby collecting of common rocks, panning, or a fee dig).
- Ready with conditions: the activity is supported, but something must be done first, such as buying a permit, booking a slot, or staying within a daily limit.
- Research: the place is known for a material, but we have not yet confirmed current access or collecting rules. These records are useful for study and planning, not for a trip.
- Protected: collecting is not allowed, for example in national parks, many state parks and sensitive fossil sites. These places stay on the map for viewing, learning and to warn visitors.
A fuller explanation, with examples, is on how map statuses work.
How a place becomes Ready
- We identify the exact site and who manages it.
- We find the manager’s or operator’s own published rule or page and record its address.
- We confirm the activity is allowed for the public, and note any permit, fee, season or limit.
- We record the date of the check.
- Where the site is public or the operator invites visitors, we add exact coordinates. Otherwise the place is shown at county or area level.
How often records are checked
Ready and Ready with conditions places are re-checked on a rolling schedule, with fee sites and seasonal sites checked before each season. Each place page shows its last checked date. When a visitor reports a change, the place is checked again as a priority.
Map precision
We show an exact marker only where the location is public or the operator invites visitors. Historical mine and occurrence records are often shown at county level, both because their old coordinates can be inaccurate and because many sit on private land or active claims.
What we do not do
- We do not change a status in exchange for payment or advertising.
- We do not publish exact locations of sensitive fossil or archaeological sites.
- We do not copy listings, text or photos from other websites.
Corrections
If something is wrong, tell us through the contact form. Our corrections policy explains what happens next.