EISCO 6PK Oolitic Limestone, Sedimentary Rock Specimens - Approx. 1" - Geologist Selected & Hand Processed - Great for Science Classrooms - Class Pack

I purchased this to enhance my triops' aquarium, and they've been fantastic! The hand-processed quality and unique oolithic texture make them visually appealing and a great addition to the habitat. The rocks are the perfect size for small tanks, and my Triops enjoy exploring them while it also helps maintain the pH of the water. Highly recommended for aquarium enthusiasts and educators!

This rocks are pretty decently sized. I actually got 13, so I think that shows you’ll definitely get the 12. The value is there for the price, aquarium limestone was 3x the price at my local fish store. These work in my fish tank at increasing my kH and pH slightly. It helps stabilize the tank water and I’ve noticed it working.

I love demonstrating for students how acid dissolves limestone. It felt like a lot of money for six little pieces of limestone (to someone who used to live where every streambed was full of limestone pebbles!) -- but each stone can be used more than once, as there's no need to let it sit in the vinegar until it disappears, so there's that. I still want to ask a friend in Indiana to just send me a bag of rocks for the price of postage.

We used these limestone rocks for my son’s science fair project. We were testing the effects of acid rain/pollutants on dissolving rocks. And these rocks were perfect for it! Fairly similar in size so we could measure and weight to keep track of the variable for the project. I can see how they could be used for other purposes too. They were nice and shiny. Very good quality.

Ground this for a chemical reaction. It works very well!

My daughter purchased these rocks for a science experiment. She was sure that soda would discolor them if they were left submerged overnight. They did not discolor at all. So we now have a few special rocks on are backyard and she has a few less dollars in her piggy bank. Why did you pick this product vs others?

Good product

These pieces are small, which is what I was looking for for my isopods. These are great value as long as you know that beforehand though!

Pretty disappointed that one of the 12 rocks was the size of a pebble! I thought it was a little piece of debris or a piece of rock that broke off another one but no because there’s only 11 other rocks aside from this in the bag, so this is actually considered one of 12 rocks. There’s 5 others that are not much bigger than this one as well. I actually only got 6 rocks that were the size they were supposed to be as mentioned in the listing description and 6 that are MUCH smaller. The bag in the background behind my hand has all the rocks in it and look how small that bag is in comparison to my tiny female hands. Pretty disappointed especially with how expensive this bag of rocks was.