I'm interested in fluorite (Since Fluorine is my favorite element, and I wanted a sample of it, even if bonded, but I don't want to buy it; that would be no fun), and I'm curious if it can be found on Long Island, New York. Where would the largest geologic formations be that are accessible?
I do not know of fluorite being reported to occur on Long Island. If fluorite is found in NYC, the Natural History museum might have specimens. You might try contacting a mineralogy / mineral collecting club on Long Island. Someone there would probably know for certain if fluorite can be found.
Personally, I have collected fluorite from the Penfield Quarry near Webster New York during the mid 1980s. Some of the waste rock from the quarry was used as breaker wall stone on the lake front in Webster New York. You could probably still collect fluorite crystals there.
Here is a map of the lower 48 states showing mines where fluorite has been reported to occur.
Other places I have personally collected fluorite
Terlingua, Texas fluorspar mine (massive bedded fluorite)
Spearfish Canyon Black Hills South Dakota (fluorite in geodes in limestone)
Closed rock quarry in Pennsylvania near Breezewood, PA
Locations where fluorite is still able to be collected.
Mines/Mountains near Socorro New Mexico
Mt Antero in Colorado, at high elevation.
Bancroft Ontario - fluorite in calcite (fluorspar)
Burin Peninsula, Newfoundland, Canada (fluorspar)
Maps created using Digital Rockhounds Companion software.
Long Island is one giant moraine so finding anything specific is basically a needle in a haystack without a really detailed survey and even then it is mostly luck.
PS: you are fairly close to the Franklin Mineral and Sterling Hill Mining Museum where you can find some really rare fluorescent minerals in the old talus piles, including fluorescent fluorites, and you can search them for a nominal fee.