There is not enough information to go on. Many minerals fit this description, especially since there are several types of nonmetallic luster.
magnetite
Magnatite is the mineral that has a nonmatallic luster, is black, and can be scratched by a fingernail.
Depending on the variety, feldspars can range from adamantine to glassy in luster.
If a mineral has a shiny luster, is it matallicIf a mineral has no shiny luster, is it nonmetallic?
Gypsum
luster
hematite can have both metallic and nonmetallic luster.
That could be graphite, which is a natural allotrope of the element carbon.
The Luster of a mineral is it's appearance in the light. Also there are two types of Luster, metallic and nonmetallic.
luster is used to determine if a mineral has metallic or nonmetallic shine. It also means the way a mineral reflects light
true
yes