Delindeite

Delindeite is a very rare titanium sorosilicate mineral in the lamprophyllite group and seidozerite supergroup. It was named in honor of Henry Samuel de Linde, an amateur mineralogist who was the former owner of the Diamond Jo quarry, Arkansas, where the mineral was first discovered in 1987. It is a secondary mineral formed under oxidizing conditions from a titanium-bearing nepheline and syenite. Delindeite is also part of a rare group of minerals called titanosilicates. With only around 30 known species discovered as of 2025, they are quite diverse. Delindeite specifically is a barium titanosilicate. Other than Diamond Jo quarry, delindeite has also been found at the California State Gem Mine in San Benito County, California.