80 NOTES ON TA8MANIAN MINERALS. 



15 NiccOLiTE. — (Nickel Arsenide.) 



This ore has been obtained in small quantity near 

 Trial Harbour, West Coast. 



16 PiLOTiTE. — (Hydrated silicate of alumiiiiuni and 



manganese?) 

 An altered variety of actinolite, known as "rock 

 cork." It occurs in felted fibrous masses of a pale 

 grey to almost white, in considerable quantity 

 east of the "Red Face"' at the Mt. Bischoff Tin 

 Mine, Mt. Bischoff. 



17 Plinthite.- — (Hydrous aluminium silicate.) 



An amorphous clay-like substance of a brown colour, 

 with conchoidal fracture. Near Falmouth, East 

 Coast. 



18 FiMEhiTF..— (Hydrated magnesiuni and nickel 



sUicate.) 

 As an incrustation attached to other nickel minerals. 

 Near Trial Harbour, West Coast. 



19 Proustite. — (Silver sulpharsenite.) 



At the Oonah Mine, Zeehan, this mineral, which 

 is commonly known as "ruby silver," has been 

 obtained in bunches of minute perfectly-formed 

 rhombohedral crystals of remarkably bright red 

 colour. They are implanted on cavernous masses 

 of pyrites, and are readily detected by the con- 

 trast of colour. Under the low power of the 

 microscope they form most attractive objects, the 

 crystals being extremely sharp and distinct. They 

 rarely exceed two to three millimetres in length. 

 Minute crystals have also been noticed at the 

 Magnet Mine. 



20 Pyrargyrite. — (Silver sulphantimonite.) 



At the Magnet Silver Mine this mineral has 

 recently been obtained in small but perfectly- 

 formed characteristic rhombohedral crystals 

 nestled in cavities in the lode gangue associated 

 with galena and blende in the southern working 

 of the mine. They are dull black in colour, due 

 to tarnish, but readily give the bright red streak 

 as well as the conchoidal fracture when broken. 

 The mineral in its compact and investing forms 

 is not by any means rare, but the crystals are 

 extremely so ; in fact they appear to be first 

 detected in this state. 



