Whole window SHGC is lower than glass-only SHGC, and is generally below 0.8. Solar heat gain can provide free heat in the winter but can also lead to overheating in the summer. How to best balance solar heat gain with an appropriate SHGC depends upon the climate, orientation, shading conditions and other factors.
Eakle, A.S. (1929), Probertite, a new borate, American Mineralogist: 14: 427-430. Schaller (1929) USGS Professional Paper 158: 137. Foshag (1931) American Mineralogist: 16: 338. Barnes (1949) American Mineralogist: 34: 19, 611. Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II.
Apatite is a spiritual stone that helps to strengthen the intellect thereby giving insight into the intuitive worlds. It helps to balance the polarities in our lives and bring harmony. Relieves tension and grief helping the wearer get to the root cause enabling them to work with energies to clear blockages.