COLORS of PORPHYRY
Rhyolite porphyry = porfido rosso laterizio (Italian name).
Guarried at the Wadi Abu Gerida quarry, Eastern Desert, Egypt, first time used during the Roman period.
It's a less commonly used variety of "red" porphyry, has pinkish brown matrix with pink & blue
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Andesite-dacite "imperial porphyry", reddish purple matrix with white & pink.
Ancient names: lapis porphyrites & rubet porphyrites
Italian name: porfido rosso [anticoor Egiziano]
Used minor in Predynastic to Early Dynastic Periods, heavily used since Roman Period.
2/
Andesite-dacite green porphyry, Porfido Verde Egiziano (It.)
Roman name - lapis hieracitis. Has greenish black matrix with white & pale green.
Used first in Roman period; quarry at Mons Porphyrites, Eastern Desert, Egypt. The best known from the opus sectile decorations, Ravenna.
Dolerite porphyry, greenish black with light gray to greenish gray (1st 📷). Was used in Late Period’s 30th Dynasty & early Ptolemaic Period; ancient name unknown.

Pictures 2nd & 3rd - two varieties of the andesite-dacite green porphyry (Ravenna 👆)
Two varieties of black andesite porphyry. Incorrect name: breccia, ancient name unknown.
Used from Predynastic to Early Dynastic Periods. As an example two jars from Egypt. I would love to have the one with yellow :-)
The last one, 10th color / variety of porphyry - trachyandesite porphyry, black matrix with pale gray.
Roman name - possibly knekites, Italian name - porfido serpentino nero (do not confuse with serpentinite!).

source: Ornamental Stones, Harrell, James A. https://escholarship.org/uc/item/4xk4h68c#main
My favorite examples of use the porphyry - portable altars 🤗
You can find more on profile @salu1292 https://twitter.com/salu1292/status/1258860633207894016?s=20
Great thread about a red (Imperial) porphyry https://twitter.com/incunabula/status/1258745806754131968?s=20
You can follow @ColorsAndStones.
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