If you find yourself enchanted by these garden gems, here are a few tips to help you choose the right hydrangea and keep it ...

A chemical and spectroscopic comparison of two purple gem spinel samples, one of them the first reported example of a spinel with a saturated purple color caused predominantly by chromium and cobalt.

Feature Gems & Gemology, Spring 1992, Vol. 28, Issue 1 Natural-Color Nonconductive Gray-to-Blue Diamonds Emmanuel Fritsch and Kenneth Scarratt ...