Hulsite

Hulsite Comments: Black crystalline granular massive hulsite. Location: Brooks Range, Seward Peninsula, Alaska, USA. © Jeff Weissman / Photographic Guide to Mineral Species

Chemical Formula: (Fe2+,Mg)2(Fe3+,Sn)(BO3)O2
Locality: Brooks mountain, Seward peninsula, Alaska.
Name Origin: Named for Alfred Hulse Brooks (1871-1924), U. S. Geologist.

Physical Properties

Cleavage: {110} Good
Color: Black.
Density: 4.3
Diaphaneity: Opaque
Hardness: 3 – Calcite
Luminescence: Non-fluorescent.
Luster: Sub Metallic
Streak: black

Photos:

Hulsite with Siderophyllite Locality: Brooks Mountain, Seward Peninsula, Alaska (Type Locality for Hulsite) Description: Rich specimen of lustrous black hulsite crystals with green siderophyllite crystals. Overall Size: 17x12x12 mm Crystals: micro © AllMinerals/JohnBetts-FineMinerals
The origin of this sample is Seward Peninsula, Brooks Mountain, Alaska. The sample measures about 10 cm across. The sample is on display in the Smithsonian Museum of Natural History.
Titovskoe B deposit, Tas-Khayakhtakh Range, Dogdo River Basin, Polar Yakutia, Sakha Republic (Saha Republic; Yakutia), Eastern-Siberian Region, Russia © Pavel M. Kartashov