what is Howlite , how to select Howlite

=================================================================================================

General Howlite Information
 Chemical Formula:  Ca2B5SiO9(OH)5 
 Composition:  Molecular Weight = 391.32 gm 
    Calcium   20.48 %  Ca   28.66 % CaO 
    Silicon    7.18 %  Si   15.35 % SiO2 
    Boron     13.81 %  B    44.48 % B2O3 
    Hydrogen   1.29 %  H    11.51 % H2O 
    Oxygen    57.24 %  O 
             ______        ______  
             100.00 %      100.00 % = TOTAL OXIDE 
 Empirical Formula:  Ca2B5SiO9(OH)5 
 Environment:  Secondary mineral in arid environments. 
 IMA Status:  Valid Species (Pre-IMA) 1868 
 Locality:  Tick Canyon, Los Angeles Co., California. Link to MinDat.org Location Data. 
 Name Origin:  Named after Henry How of Nova Scotia when he first described it in 1868. 
 Synonym:  ICSD 15178     PDF 26-1404 

If this guide is helpful, please mark it "helpful" end of the article.Thank you!

Physical Properties of Howlite 
 Cleavage:  None 
 Color:  Colorless, White. 
 Density:  2.58 
 Diaphaniety:  Translucent 
 Fracture:  Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments. 
 Habit:  Earthy - Dull, clay-like texture with no visible crystalline affinities, (e.g. howlite). 
 Habit:  Massive - Uniformly indistinguishable crystals forming large masses. 
 Habit:  Nodular - Tuberose forms having irregular protuberances over the surface. 
 Hardness:  2.5-3.5 - Finger Nail-Copper Penny 
 Luminescence:  Non-fluorescent. 
 Luster:  Earthy (Dull) 
 Magnetism:  Nonmagnetic 
 Streak:  white 

Calculated Properties of Howlite 
 Electron Density:  relectron=2.62 gm/cc
note: rHowlite =2.62 gm/cc.
 
 Fermion Index  Fermion Index = 0.03139
Boson Index = 0.96861 
 Photoelectric:  PEHowlite = 2.97 barns/electron
U=PEHowlite x relectron= 7.79 barns/cc.
 
 Radioactivity:  GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Howlite is Not Radioactive
 

If this guide is helpful, please mark it "helpful" end of the article.Thank you!