To emphasize its cosmic rotation, the set of twelve zodiac symbols are traditionally arranged around the rim of a wheel. The hub represents the geocentricity of earth the four spokes make the Zodiac Cross.
Like crosses seen in many other symbols, this does not necessarily relate to Christianity. (See for example, the Kabbalah Cross)
The four spokes point to zodiac symbols associated with the equinoxes and solstices of winter, summer, spring and autumn. The equivalent old Babylonian symbols may relate to the four images in the Hebrew Bible, which are linked to the four Evangelists of Christ; Matthew, Mark, Luke and John. (See Evangelists Cross) There's a whole pile of speculation in much of this, but many people like to see a link between astrology and Jesus.
Earlier civilizations, particularly in Asia, have attributed gemstones with magical properties and astrologers have assigned gems of certain colours to the twelve signs. From this, and with the helpful support of jewelry makers, we have the Birth Stone Cross.
Setting aside, if we dare, the risk of committing one of the seven deadly sins, if any meaningful and beneficial message can be gleaned from this, then that must be a good thing. But to assume some 'secret' message can be revealed by connecting astrology with Christianity, is frankly a waste of time.
There is no secret in Christianity.
Let me repeat that. There is no secret in Christianity.
God has a very clear message for us. He does not speak to us in riddles. He does not give messages that may take thousands of years to decode.
When anybody has an important message to relate, a really important life-or-death message, it makes no sense to speak in riddles. God's message is 100% clear.
All we have to do is open our eyes.