ˈthäləˌnīt noun
( -s )
Etymology: French thalénite, from T. R. Thalén died 1905 Swedish physicist + French -ite
: a mineral Y 2 Si 2 O 7 or 2Y 2 Si 2 O 7 .H 2 O consisting of an yttrium silicate and occurring in flesh-red monoclinic crystals possibly isomorphous with thortveitite (hardness 6.5, specific gravity 4.2)