Porphyry, any igneous rock consisting of large crystals in a mass of much smaller crystals. The large and small crystals usually are of different minerals; the rock is generally named according to its major component (for example: granite porphyry). When cut and polished, porphyry has a beautiful pattern and contrast of colors. It is used for tombstones and ornamental panels.
One was a celebrated author, the other a famed physicist. What the two shared was a public exposure of their religious beliefs. Big E had an on-again, off-again relationship with God, while C.S. was an avowed atheist during his early years.
He may have been born in Brooklyn, but Carl Sagan was gunning for the stars as soon as he arrived in this world. Get to know the scientist whose infectious delight in the universe still holds us spellbound.