Barringer had already shipped off 1000 pounds of gadolinite and other minerals to see if anyone could figure out what they were and whether they had any value, but was disappointed with the evaluation.
To my great surprise, the first pick I put in the ground brought to the surface a huge crystal of gadolinite, and for a short time I enjoyed the most pleasant excitement, bringing out crystal after crystal from the decomposed feldspar, until the pile must have weighed 30 pounds.
This good news spurred further searching which turned up large quantities of fluorite, muscovite, magnetite, menaccinite, molybdenite, graphite, columbite, allanite, several more pounds of fergusonite and ultimately over 200 pounds of gadolinite. (In 1895 Niven arranged the purchase of the Barringer Hill deposit from John Barringer, on behalf of Thomas Edison's Piedmont Mining Company, for $5,000 in gold coin.
(1984) A refinement of the crystal structure of gadolinite. American Mineralogist, 69, 948-953.
(1974) Mineralogie de la France (allanite, bastnasite, gadolinite, monazite, parisite, synchisite).