Rockhounding at Herkimer Diamond Mines, New York
ALLOWED
No permit required
Key Conditions
- Private fee-dig: a day ticket ($19 ages 13+, $16 ages 5–12 on weekdays; +$3/+$2 Friday–Sunday) is the only permission needed, and you keep everything you find
- Hand tools only, up to a 12-lb sledge. Powered equipment is banned, and closed-toe shoes are required.
- 2026 season: April 12 to October 31, 9 a.m.–5 p.m. daily. The mine closes during snow, sleet, heavy rain or thunderstorms.
- The neighboring Ace of Diamonds Mine is closed for the entire 2026 season, so do not plan a two-mine day on NY-28 this year
- Roadcuts and state land are not an alternative: 6 NYCRR § 190.8(g) bars removing rock, minerals or fossils from DEC-managed state land without a permit
2026: one of the two NY-28 mines is closed all season
Ace of Diamonds Mine, next door to Herkimer Diamond Mines in Middleville, says its mine, campground and gift shop are closed until further notice, and it expects no mining for the entire 2026 season. Earlier in the litigation, a court ruled that the injunction halting its commercial mining had been improperly issued. The case is still pending, though, and the mine says the property may be sold at auction or divided between landowners. Many older trip guides still recommend doing both mines in one day. For 2026, Herkimer Diamond Mines is the walk-up option on this stretch of NY-28.
Herkimer Diamond Mines at a Glance (2026)
None
Permit needed
$19–$22
Adult ticket
Ages 13+, weekday vs. Fri–Sun
Apr 12–Oct 31
Season
9 a.m.–5 p.m.
Hours
12-lb sledge
Tool limit
No powered equipment
All of them
Keep finds?
Herkimer Diamond Fee-Digs Compared (2026 Season)
| Mine | Location | Adult price | Booking | 2026 status |
|---|---|---|---|---|
| Herkimer Diamond Mines | NY-28 N, Middleville area | $19 weekday / $22 Fri–Sun (13+) | Walk-up, 9–5 | Open Apr 12–Oct 31 |
| Ace of Diamonds Mine | Middleville, adjacent on NY-28 | $14 (8+), last posted | Walk-up | Closed all season |
| Crystal Grove Diamond Mine | St. Johnsville (Fulton County) | $16 (12+) non-camper | Walk-up; campground on site | Mid-April–mid-October |
| Diamond Mountain Mining — Wilderness Dig | 416 Ritter Rd, Little Falls | $120 (14+) / $30 (13 and under) | Reservation only | Open 7 days, 2026 season |
Prices and status taken from each operator's own website on September 17, 2026. Fee-dig pricing changes often, so confirm before driving.
Herkimer diamonds aren't diamonds, and they don't come from Herkimer village. They are quartz crystals that grew inside cavities (vugs) in the Little Falls Dolostone. That Upper Cambrian carbonate rock was laid down in a shallow sea roughly 495 million years ago and today crops out across the Mohawk Valley. The crystals formed much later than the rock around them. Because many grew in open cavities without attaching to a wall, they are doubly terminated, with 18 faces, and clear enough to look faceted.
That geology shapes how you dig. Crystals from the loose fill on the surface have usually been picked over. The unbroken slabs are where the reward is. A slab with a dark, sooty seam or a visible pocket is worth splitting along its bedding plane. An unopened vug can hold several loose crystals in the clay or black residue at its center, and a broken one usually doesn't.
From a legal standpoint, this is one of the simplest pages on the site. The mine is private property, admission is the permission, and nothing you find has to be declared, weighed or reported. The legal trap is the idea that you can skip the fee: the dolostone that shows in roadcuts and outcrops is either someone's private land or state land, where DEC's rules forbid removing any mineral.
Why the free roadcut isn't free
Under 6 NYCRR § 190.8(g), no person may "deface, remove, destroy or otherwise injure" any "rock, soil, fossil or mineral" found on State land. The rule's only exceptions are for personal consumption or for a permit issued jointly by the DEC Commissioner and the Commissioner of Education under Education Law § 233. Neither is a practical route for a weekend crystal hunt. Outcrops that aren't state land are generally someone's private property, and digging there without the owner's permission is trespass. The fee-digs exist because they're the one place where the landowner's permission comes with the ticket.
What to Bring to the Mine
- RequiredSafety glasses— The mine recommends them, and dolostone chips are sharp. Buy ANSI Z87.1-rated wraparounds, not sunglasses.
- RequiredClosed-toe boots— Required by the mine. Steel or composite toes are worth it when you're moving slabs.
- OptionalCrack hammer (3–4 lb) and cold chisels— A loaner hammer is included with admission. Bring your own chisels to split slabs along bedding planes.
- OptionalSledgehammer, 12 lb maximum— For opening big boulders. Anything heavier, and any powered tool, is banned.
- RequiredWork gloves— Leather, not cotton. Crystal edges cut straight through knit gloves.
- RequiredPadded specimen containers— Egg cartons or tissue-lined boxes. A loose bucket chips terminations on the drive home.
When to Dig
Spring (Apr 12–May)
GoodFreeze-thaw over the winter splits rock and exposes new material, so the first weeks after opening day on April 12 turn up crystals that weren't visible in October. The ground is often muddy.
Summer (Jun–Aug)
FairThe busiest months, especially Friday–Sunday, when tickets cost more too. The quarry floor holds heat, so bring water and start at 9 a.m.
Fall (Sep–Oct 31)
GoodCooler, thinner weekday crowds and weekday pricing. The season ends October 31, and cold rain can close the mine on short notice.
Winter (Nov–Apr 11)
ClosedMining is closed. With Ace of Diamonds also closed for 2026, there's no walk-up alternative on NY-28 until the spring 2027 openings.
Hunt the morning after rain
Rain washes the dust off the tailings, and a clear quartz crystal catches the low sun in a way a dry one never does. On the first sunny morning after a rainy night, walk the base of the piles slowly with the sun behind you before you swing a hammer at all. Look for sparkle in the gray fines. Keep in mind that the mine closes during harsh rain and thunderstorms, so the rain has to have stopped before you go.
Permits & Licenses
| Permit | Required? | Notes |
|---|---|---|
| Mining admission (day ticket) | Yes | This is an admission ticket, not a government permit. No reservation is needed: sign in at registration any time between 9 a.m. and 5 p.m. The ticket covers all-day prospecting, collection bags and the use of a rock hammer, which is loaned in exchange for an ID. |
| State or county rockhounding permit | No | None is needed for digging on private fee-dig ground with the owner's permission. We found no New York statewide recreational mineral-collecting license. |
| DEC state land collecting | Yes | Removing rock, soil, fossils or minerals from state land requires a permit from both the DEC Commissioner and the Commissioner of Education under 6 NYCRR § 190.8(g). There is no casual-collecting allowance for recreational rockhounds. |
Time & Seasonal Restrictions
- No powered equipment, and no tool heavier than 12 lb. You may bring chisels, screens, small shovels, buckets and hammers up to a 12-lb sledge.
- Closed-toe shoes are required. Eye protection isn't mandatory, but the mine strongly recommends it.
- Children under 16 need adult supervision, and children aged 4 and under aren't issued tools
- Open April 12 to October 31, 2026, 9 a.m.–5 p.m. The mine closes in unsafe weather, including snow, sleet, harsh rain and thunderstorms.
- Ace of Diamonds Mine (Middleville, less than a mile away) says its mine, campground and gift shop are closed until further notice, and it expects no mining for the entire 2026 season
- Diamond Mountain Mining's Wilderness Dig in Little Falls is by reservation only and bans power tools and pets (service animals excepted)
Equipment Notes
- Safety glasses. Dolostone breaks into sharp flakes, and splinters fly from every sledge blow.
- Leather work gloves. Crystal edges and freshly broken rock cut bare hands.
- A 3- to 4-lb crack hammer plus a cold chisel or two for splitting slabs along bedding planes. Use the sledge (12-lb maximum) only for breaking big boulders open.
- Egg cartons, paper towels or a padded box. A doubly terminated crystal loses its points if it rattles loose in a bucket.
- A small screen or sieve for the loose fill at the bottom of the tailings. Loose crystals turn up there after rain.
- Knee pads, and old clothes you don't mind ruining. The fines turn into gray mud when wet.
What People Find Here
- Herkimer diamonds: water-clear, doubly terminated quartz crystals with 18 natural faces (six at each end and six prism faces around the middle). Most are pea-sized to thumbnail-sized.
- Crystals containing black anthraxolite (hydrocarbon) inclusions, and occasional fluid-inclusion crystals with a moving bubble
- Clusters of intergrown crystals, and 'skeletal' or smoky specimens
- Vug-lined dolostone matrix specimens with crystals still attached, often the most striking display pieces
Penalties for Violations
← Scroll to see all columns
| Violation | Statute | Penalty |
|---|---|---|
| Using power tools or tools heavier than 12 lb in the mining area | Herkimer Diamond Mines posted mine rules | Private-property rule; the operator can require you to stop or leave the mining area |
| Removing rock, minerals or fossils from DEC-managed state land without a permit | 6 NYCRR § 190.8(g) | Violation of DEC state land regulations, enforced by DEC Forest Rangers and Environmental Conservation Officers under the Environmental Conservation Law. We could not confirm the exact fine schedule for this subsection, so contact DEC before assuming a figure. |
| Digging on private land or a closed mine without the owner's permission | N.Y. Penal Law § 140.05 (trespass) | Trespass is a violation punishable by up to 15 days in jail and/or a fine |
Etiquette & Leave No Trace
- Don't break a boulder someone else is already working on
- Leave the crystals you don't want on top of the pile rather than grinding them underfoot. A child will be thrilled to find them.
- Wear eye protection when you swing a hammer, and tell anyone within 10 feet before you do
- Stack the broken rock you've finished with out of the walkway
- Return the loaner hammer. Your ID is sitting at registration until you do.
- Don't sell what you mine. Ace of Diamonds forbids 'mining for the purpose of resale,' and it's good form at every fee-dig.
Frequently Asked Questions
Do I need a permit to dig for Herkimer diamonds?
No. Herkimer Diamond Mines is a private fee-dig, and the day ticket is the only permission required. We found no New York recreational mineral-collecting license that would apply.
Is Ace of Diamonds Mine open in 2026?
No. As of September 2026, Ace of Diamonds says its mine, campground and gift shop are closed until further notice, and it expects no camping or mining for the entire 2026 season. The mine hasn't published a reason for the closure, but its site also describes ongoing litigation in which the property may be sold at auction or divided between the current landowners. Its online store is still open.
Can I collect Herkimer diamonds from roadcuts along NY-28 or on state land?
Not on state land. 6 NYCRR § 190.8(g) prohibits removing any rock, fossil or mineral from DEC-managed state land without a permit from both the DEC and Education commissioners. Most of the rest of the Little Falls Dolostone outcrop is private, so the fee-digs are the only reliably legal places to hunt.
How much does Herkimer Diamond Mines cost in 2026?
$19 for ages 13 and up and $16 for ages 5–12 on weekdays, with $3 and $2 added Friday through Sunday. Kids 4 and under get in free. A rock hammer is included.
Where in the pile are the best crystals?
Inside unbroken dolostone. The crystals formed in cavities (vugs) within the rock, so a boulder that sounds hollow or shows a dark seam is worth splitting. The loose fines at the base of the tailings also collect crystals that rain washes out, especially the morning after a storm.
Can I bring my own sledgehammer?
Yes, up to 12 lb, along with chisels, screens, small shovels and buckets. Anything powered is banned.
New to This? Start Here
Disclaimer
Information is provided for general guidance only. Regulations change frequently. Always verify current rules with the official jurisdiction before relying on this information for legal decisions. Permitted Pursuits is not a substitute for official agency guidance. Report an error.
Sources
- Herkimer Diamond Mines — Mine (prices, 2026 season, tool and safety rules)(accessed 2026-09-17)
- Ace of Diamonds Mine & Campground — Mining page and 2026 closure announcement(accessed 2026-09-17)
- Diamond Mountain Mining — Wilderness Dig(accessed 2026-09-17)
- Crystal Grove Diamond Mine & Campground — Rates(accessed 2026-09-17)
- 6 NYCRR § 190.8 — State lands, general (Cornell LII)(accessed 2026-09-17)
- New York State Geological Association 1972 Guidebook — Little Falls Dolostone (Upper Cambrian), H. S. Muskatt(accessed 2026-09-17)
Last verified: 2026-09-17 · Last updated: 2026-09-17