Discourse on Mystran Symbology
Dissertation for Doctorate of Ancient History and Thamaturgy
by
Luxor Arcanum - Faithful Servant of Mystra

There are several different versions of the Mystran Holy Symbol.  The original symbol was a single blue-white star worn by followers of the faith before the time of troubles.

 


This is known as the old symbol and is still accepted as an article of the faith. (From the Luxor Arcanum sigils development archives):

All new sigils being made by the church consist of the new symbol, "a circle of stars in a ring, with red mist rising toward (or flowing from) the center."  (Grand Sage Greenwood & Arch Sage Grubb, Running the Realms, p.47).  Yet, the absolute number of stars varies.  The Tome Faiths and Avatars lists the symbol as "circle of nine stars, with a red mist rising toward (or flowing from) its center or a circle of seven blue-white stars, or (older) a single blue-white star" (Sages Martin & Boyd, Faiths and Avatars, p128).  Presumably the stars in the circle of nine are blue-white, yet occasionally white stars are used.  A nice example of the blue, nine ring sigil was developed by the Masters of Magic:
from the Masters of Magic

However, the Tome of "Faiths and Avatars" (Sages Martin & Boyd, p.128) also shows a rune-like drawing of a picture of a circle of eight stars, presumably developed...

... from an earlier drawing of the "Holy Symbol of Mystra" drawn alongside the holy symbols of other faiths in the Libram "Forgotton Realms Campaign Setting" (boxed set handouts)

The eight ring version can also be seen in the Manual "Running the Realms." (Grand Sage Greenwood & Arch Sage Grubb, p.47) It appears to be an inverse of the rune stone:

This eight pointed star is by far the most popular, as exhibited in the following series. This is from the Luxor Arcanum sigils development archives:

We find an interesting version from the  Servants of the Mystery Guild.  This symbol is remarkable in that it appears to have used the Running the Realms symbology, but with a marked material consistancy underneath for color.  Altogether a very nice rendering of the original.

Lastly, we see an interesting programmed illusion from "Mystra's domain" as well as the "Servants of the Mystery Guild" Perhaps this is a type of sigil appreciated by Mystrans who study the art of illusion?!

 
Finally, there is a drawing of the seven star sigil shown in "The Seven Sisters" tome (upper corner, pgs. 2-12, 62-127), however, this may instead only be symbolic of the seven sisters themselves.
 "Seven bright stars in the sky I see.
Seven for those who watch over me.
Seven be the smiles down they send.
Seven be the troubles swift they mend."

This is supported by the fact that each of the seven chosen appear to have thier respective heraldic symbols listed in the upper corner, and it makes sense that the group together would have a symbol similar the the Goddess herself. 

In the end this Temple choose the seven star sigil as the symbol for the Temple of Mystra in Raven's Bluff.  It reminds us to be accepting of all aspects of our Lady of Mysteries.  Tolerance is very important in our faith as we believe we may only press forward by learning about the past.
May the blessings of Mystra be upon you.