The World's Largest Gemstone
In Michigan, United States
Size:  (not chosen)
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Jasper Knob is commonly known as the “World’s Largest Gemstone”. The formation is a 1.874 billion-year-old rock outcrop in the city of Ishpeming, Michigan, and is accessible by a foot trail. Please park on the north side of the road near the intersection of Hill and Jasper streets. Enter the trail using the steps through the wall of stone. A common misconception of the area is that a local mining company owns it. In fact, the property is owned by the city of Ishpeming.
The world’s largest gemstone is a banded iron formation (BIF) that is comprised of jaspilite, which consists of alternating bands of jasper (a cryptocrystalline quartz), red hematite, and silvery-gray specular hematite. This type of iron ore is not profitable for mining because the iron content is only about 40%. Thus, this beautiful example of natural occurring gemstone is preserved for all to visit and admire.
Enjoy your visit to Jasper Knob!
Logging Requirements to be emailed to the cache owner:
First, give us the size of the entire exposed BIF at the top of the hill, in paces. That is, count the number of steps it takes to go from one side to the other. Give both the N/S and E/W dimensions.
Next, give us the elevation reading from your GPSr at the top of the formation.
Finally, upload a photo of yourself and your GPSr with the jaspilite formation in the background.
In order to keep with the spirit of Earth Caches, these requirements must be met in order to claim a find, just as signing a logbook is a requirement to claim a find on a traditional cache. Thanks for understanding!
(No hints available.)
Last Updated: on 10/6/2017 6:56:45 PM Pacific Daylight Time (1:56 AM GMT)
Coordinates are in the WGS84 datum