The mechanical property of pure titanium changes by an addition of O and Fe.
The more the quantity of addition will be, the stronger material will be. However, ductility will be lower. Then it is necessary to chose which kind of pure titanium to use, depending on your use.
For optical frames, JIS Grade 2 is used popularly. JIS Grade 1 is used by some of those who put importance to formability.

[Physical quality of pure titanium]
Melting pointij 1,668
Crystal structure HCP885@BCC
Density i/3j 4.51
Atomic number 22
Atomic weight 47.90
Youngfs modulusikgf/mm2j 10.85~103
Poissonfs ratio 0.34
Electrical resistanceiʃ-cmA20j 47_55
Electrical conduction icompared to CuAj 3.1
Hheat conductionical/cm2/sec//cmj 0.041
Linear expansion coefficienticm/cm/A0_100j 8.4~10-6
Specific heatical/g/Cj 0.12


Grade Chemical components@ Stretching test
H O N Fe Ti Thickness(mm) Tensile strength(N/mm2) Y.P.(N/mm2) Elongationij
Grade P 0.013 0.15 0.05 0.20 Bal. 0.2@@T QVO_SPO 165 27
Grade Q 0.20 0.25 RSO_TPO 215 23
Grade R 0.30 0.07 0.30 SWO_UQO 345 18
Grade S 0.40 0.50 TTO_VTO 485 15