122 GUIDE TO THE AUSTRALIAN MUSEUM. 



5. Epidote group ; Ex. Epidote, a dark green mineral, which is 

 sometimes good enough to cut for a gem. 



6. Mica group ; This affords a transparent and tough substitute 

 for glass, and is used in stoves and lamps. 



7. Talc group ; Ex. Steatite, Figure stone, &c. 



8. Sepiolite group ; Ex. Sepiolite (Meerschaum). 



9. Serpentine group ; Affords pretty ornamental stones when 

 polished. 



10. Chlorite group ; Ex. Chlorite, a mica-like mineral found in 

 some schists and other rocks. 



11. Felspar group ; An extensive group including: — 



Orthoclase, one of the components of granite. Moonstone, 

 Sunstone, Amazonstone are varieties of the same. 



Labradorite and Oligoclase, which occur in many eruptive 

 and volcanic rocks. 



12. Andalusite group ; Ex. Chiastolite or Mascle, Cyanite, a 

 beautiful blue semi-precious stone. 



13. Staurolite group ; Ex. Staurolite, or Cross Stone. 



Silicates containing other Acids (Boracic Acid, Hydrofluoric 

 Acid, Hydrochloric Acid, Sulphuric Acid), besides Silicic A.cid, 

 including as principal groups : — 



1. Datolite group ; Ex. Datolite, Danburite. 



2. Axinite group ; Ex. Axinite, crystals in the shape of axe- 



heads. 



3. Tourmaline group ; Ex. Tourmaline, often in company with 



stream tin. 



4. Topaz group ; Ex. Topaz, blue, white, and yellow varieties. 



5. Ultramarine group ; Ex. Ultramarine, or Lapis Lazuli, 



affording a beautiful ornamental stone and a rich blue pig- 

 ment, which is also manufactured artificially. (See 

 Catalogue pages 89 to 44, Nos. 1055 to 1105.) 



