Denver Gem & Mineral Guild

Mineral Identification

Looking for help on identifying a rock or mineral in your collection? We often receive emails asking if we can identify a rock or mineral from an attached photo.  Unfortunately, we are just not set up to handle those online requests. Plus, many rocks and minerals may require more than just a photo for proper identification. Here are our best suggestions for finding the help you need . . .

Bring it to One of Our Meetings – Here you can meet several of our members who would be happy to look at it and tell you not only what it is, but also tell you where you might be able to dig for more of them, how rare or common it might be, how much it might cost in a rock shop, whether it might glow in the dark under a UV light, how it might be cleaned or polished, and the many different ways it could be turned into a piece of jewelry.

Visitors are always welcome! We generally meet the second Friday of the month. See location and directions here, but always check the home page for any schedule changes/updates.

Bring it to Our Show – Bring your mystery mineral to one of our Shows! There we have a free Mineral Identification Table where we attempt to answer all of your mineral id questions. See details on our February Show and our September Show.


Left – Dr. Pete Modreski identifies minerals at our September show.

Below – Watch Angela Garcia identifying minerals at our February Show.


Take Your Mineral to the Mines Museum of Earth Science – The Mines Museum is a hidden gem. If you have never been there you are in for a treat! They house the Colorado State Mineral Collection created by the Bureau of Mines in the 1890s and they serve as the state repository for Colorado’s mineral heritage, with the most extensive public collection of minerals from Colorado. They have over 40,000 items in the collection including two moon rocks collected by the Apollo 17 mission!

Admission is FREE.  They are located in the General Research Lab Building Colorado School of Mines – 1310 Maple St. Golden, CO, 80401.


Even if you can not make it to the museum, check out their Flickr page where they have over 1,200 mineral and fossil pictures. Hover your cursor over each picture to reveal the name/id of that sample. See if any of those pictures look like your rock! 

There are other places on the web where you can post pictures of your mystery rock to ask for help with identification, including:

Redit – Minerals – A subreddit dedicated to minerals. Post your favorite specimens. Ask for help IDing samples. Ask any mineralogy questions. Share mineral news. Was created in 2012 and has over 20,000 members.

Redit – WhatsThisRock – Dedicated to identifying mysterious rocks and minerals. Created in 2013 and has over 173,000 members.

Facebook – Rock and Mineral Identification for Beginners over 13,000 members, 279 posts/mo. Join to view/post/comment. This group is only for identifying specimens. Must provide mohs hardness, a clear photo in daylight, location of collection. 

Facebook – Identification of Rocks & Minerals over 203,000 members, 600 posts/mo. Join to post/comment.

DIY . . .

Online Mineral ID Class from Lumen
Check out this very nice Mineral ID Class from Lumen.  Clear and well-illustrated, this is part of their larger Geology 101 Class, It will walk you through the steps of mineral identification and includes a practice exercise to test your skills on a small set of minerals.

Mineral Society of America – Mineral Identification Key
Section 1 of this site covers mineral properties and lists the items that you will want to have as part of your mineral identification kit.
Section 2 is an interactive program that asks you yes/no questions to walk you through their mineral identification key to narrow down the identification of the 200 most common minerals that you are likely to encounter.

What if your mineral is not one of the 200 most common? Then it’s time to move to the mother lode of mineral information –  Here you will find information on all 6,000+ mineral species that have been approved by the International Mineralogical Association (as of 10/22/2022). At mindat you can search their mineral database by physical properties, chemistry, region, country, mineral association, crystal systemname, and more.  You can also do photo searches of over 1 million mineral photos, and locality searches, (like searching for localities near youfieldtrip!). Still need help? Then go to the “Identity Help” area of their “Discussions” page.  Here people post pictures of their mystery mineral and ask for help from other users on identifying it.

Want to learn more? Increase your knowledge of rocks and minerals by taking Pete’s Mineralogy Class. For just $15 a year you can join the Denver Gem and Mineral Guild, and have access to Dr. Pete Modreski’s 18-week Mineralogy Class.  As a member, you can access all the recorded classes located in the Member’s Only section of this website. In addition to the recordings, members can check out the class materials from the DGMG Library. That includes the textbook, the mineral test kit, and a collection of nearly 100 mineral samples that were used in the class. Your class teachers and fellow students are available at the monthly meetings (and by email) to answer any class questions you may have.

This class is in addition to all of the other benefits you will enjoy as a member of the Guild. Check out the first class now     —>

This page last updated on 2/19/2024

2 Responses

  1. Can you identify a crystal or mineral? I found a black piece that has 3 points and has a grainy appearance and all 3 points meet in the middle.

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