Harford County Minerals

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 Pyrite or "fools gold" is a common mineral and can be found in many types of rock environments. In the pictures above these specimens were found at the Havre De Grace Quarry .The rocks in this quarry are generally metagabbro or Baltimore Gneiss. However, that doesn't mean you won't find Pyrite in other types of rocks throughout the County. What identifies pyrite is the yellow metallic luster and its cubic crystals. Pyrite can also be found as a massive "non-crystal" specimen (see slide 3 above). 

 Laumontite is a member of the zeolite family of minerals. What is interesting with the minerals that make up this family, is their affinity for bonding with water. With laumontite if the mineral is exposed to air the crystals will turn into a white powder due to dehydration of the mineral