Ace of Diamonds Mine & Campground – Middleville, NY

Ace of Diamonds Mine

Disclosure: I was not compensated for this review.

Our family likes to check out a variety of family-friendly activities, and so last year we checked out the Ace of Diamonds Mine & Campground in Upstate New York, where you can look for Herkimer diamonds.

So what are Herkimer Diamonds?  These are “brilliant, water clear quartz crystals composed of silicon dioxide, hard enough to scratch glass”.

Dolomite limestone is the rock formation in which they are found. This rock was buried ages ago. Subsequently, surface water containing silicon seeped downward through the earth and was trapped in pockets or cavities in the dolomite rock. Under tremendous heat and pressure these crystals were formed. Weathering and erosion by glaciers and water have exposed the strata in Middleville, New York. the crystals are found mostly in rock cavities (formed approximately four hundred million years ago) but many are found in soil surrounding the weathered rocks.

The name Herkimer Diamond came about because to the untrained eye the sparkling crystals look like real diamonds and since these unique crystals are found in Herkimer County, named after the Revolutionary War General Nicholas Herkimer thus the name Herkimer Diamonds. Additionally, the Mohawk Indians, native to this area, are known as “The People of the Crystals”. (

This part mine, part campground, is located in Middleville, NY, which is approximately 1 hour and 45 minutes from Albany, NY.  Ace of Diamonds is located right on NYS Route 28, and we went right by it before realizing we needed to turn around.  Their website describes the mine as “A road cut in the dolomite rock exposing a rock ledge readily identifies our place.”

Once we parked, we headed into the gift shop to purchase our tickets.  The gift shop also has trinkets, gems, and snacks for sale, and there are bathrooms next to the shop (a must for kids and for washing up!).

The mine is a large, open area.  It begins right at the parking lot, so you don’t need to drive or hike to the mine.

We brought our own supplies.  If you can bring your own, I recommend bringing:

– eye protection and/or sunglasses
– sunscreen, hats
– pants
– knee pads or a kneeling pad (like the kind you might use for gardening)
– small collection containers
– change of clothes
– water, food

The gift shop does rent some supplies, but you may want to consider bringing your own sledgehammer, rock hammer, goggles, buckets, or gloves.  Obviously these are tools that adults only should be using, and away from kids (so you don’t have pieces chipping and flying off).

Since the mine goes right up to the parking lot, you can keep supplies in the car (such as a change of clothes, water cooler, lunch, etc).

Ace of Diamonds Mine

The kids had fun rooting around in the rocks for gems, and getting really dirty too!  Be sure to dress the kids in clothes they can get dirty, but also clothes are are ok with the possibility of getting a little ripped up too (from moving around on the rocks).  You may want to have them wear pants because you want to be careful about those little knees getting scraped up.

Ace of Diamonds Mine

We watched the kids carefully (who were 3 and 6 at the time), to make sure no one fell or got hurt on the rocks.  The footing can be unsteady and I certainly didn’t want the kids tripping and falling.

Ace of Diamonds Mine

By the time we left, we had collected a small jar of Herkimer Diamonds.  The kids collected a number of Herkimer Diamonds by sifting through the rocks without any help, and my husband was able to find some by breaking open rocks.  We found some pretty good-sized gems just by looking through rocks, which was exciting for the kids.

Ace of Diamonds Herkimer Diamond Mine

Our largest Herkimer Diamond from the trip.

Ace of Diamonds Mine

**Update** We went back to the Ace of Diamonds in August 2016.  They have built a huge new sluice, which makes it easy to sort through your buckets of material.

Ace of Diamonds

Ace of Diamonds

Overall, this was a fun and interesting day trip, and certainly a unique experience.  The kids ended up taking their ‘diamonds’ to school for show and tell!

The mine is open from 9am-5pm, April 1st to October 31st (call ahead to confirm).

Visit the Ace of Diamonds website at

Disclosure: I was not compensated for this review.

By | 2017-02-08T23:50:53+00:00 September 19th, 2014|Family Fun, Travel|6 Comments

About the Author:

Busy blogger and mom of two girls! We love traveling and the great outdoors, and are always looking for our next adventure!


  1. Kristi April 21, 2017 at 2:13 am - Reply

    Looks like a great place for an adventure and fun for all ages. Pack a picnic and head out to search for “diamonds”.

  2. Ashley April 21, 2017 at 7:48 pm - Reply

    Oh how fun!! My son would love to do this. Definitely a unique activity that one doesn’t always think to do! Will remember next time we are in NY. Thanks for sharing.

  3. KIm Croisant April 21, 2017 at 10:54 pm - Reply

    What a great family event. I haven’t been mining yet, but I hear it’s great and you can probably find something everytime you do it.

  4. Rosey April 25, 2017 at 2:52 am - Reply

    My son is 9 and he would LOVE this… It’s the perfect way to spend a day of adventure!

  5. Nancy Johnson Horn April 26, 2017 at 3:16 pm - Reply

    I think my kids would love this. We’ve been trying to teach them about rocks and minerals and my 6 year old and 11 year old would have a blast digging to find diamonds. My in-laws live in Port Jervis, so it may only be a two hour ride or so when we visit them (which we do often).

  6. valmg @ Mom Knows It All January 18, 2018 at 2:12 am - Reply

    That sounds like a really fun way to spend a day with the family. We visit upstate NY most summers for a few days, I think this is only about an hour away.

Leave A Comment