A mineral of a brownish black color, essentially a tantalo-niobate of yttrium, erbium, and cerium; -- so called after Robert Ferguson.
oewn 2023
0% interchangeable
Open English WordNet identifies the related term as a containing group, substance or whole.
A mineral of a nearly black color and vitreous luster, and consisting principally of the silicates of yttrium, cerium, and iron.
oewn 2023
0% interchangeable
Open English WordNet identifies the related term as a containing group, substance or whole.
A native phosphate of yttrium occurring in yellowish-brown tetragonal crystals.
oewn 2023
0% interchangeable
Open English WordNet identifies the related term as a containing group, substance or whole.