Fixed star:  GACRUX
Constellation:  Gamma (γ) Crux
Longitude 1900:  05SCO21	Longitude 2000:  06SCO44
Declination 1900:  -56.33′	Declination 2000:  -57.05′
Right ascension:  12h 31m	Latitude:  -47.49′
Spectral class:  M4	Magnitude: 1.63 Variable

The history of the star: Gacrux

from p.191 of Star Names, Richard Hinckley Allen, 1889.
[A scanned copy can be viewed on this webpage

Gamma (γ) Crux, Gacrux, is a star at the top of the Cross.

Gacrux is derived from “Gamma” of “Crux”.

There is little astrological interpretation and no mythology or legends associated with these large stars in Crux because the Cross was unknown to the ancients by its present title, its four chief stars being noted by Ptolemy (in Egypt where it was visible) as a part of the Centaur Centaurus, which now surrounds it on three sides. Bayer, who invented Crux in 1679, outlined it over the hind feet of the Centaur, these now are alpha (Acrux), beta (Mimosa), gamma (Gacrux), and delta Crucis (unnamed), —alpha at the foot, gamma at the top, with beta, and delta (unnamed), as the transverse.  

Etymology

Gacrux is derived from “Gamma” of “Crux”

This is also a pre-Christian, Q-R-GH (guttural) word. I suggest more a sense of cross-purposes and energies in conflict. (Isaac Mozeson).

CROSS in The Word: To quote the definition, a CROSS is an upright “beam,” with another beam “fastened” horizontally, upon which the noble Romans would CRUCIFY convicted innocents. The fastening of boards and the impaling of hands and feet, as well as the CROSS-WISE shape of a CROTCH or CROSS, all recall the term Hebrew KERES (hook, clasp – Exodus2611). Hebrew KORUS is to bow or bend (Isaiah 46:2). KAR-SOL is a joint or ankle, and KHIRSAL is to cross (one’s legs). If a beam is crucial to a CRUCIFIX or any CRISS-CROSS shape, there is KERES(H) (board, plank— Exodus2623) to consider. Derivatives: ACROSS, CLASP, CREASE, CRESCENT, CRISP, CROCHET(Y), CRUISE, CRUSADE, CRUSADO, CRUX and LACROSSE. [Isaac Mozeson, author of The Word, Dictionary].

The astrological influences of the constellation Crux

Crux is said to give perseverance, but many burdens, trials and responsibilities, together with much suffering and many hardships. In connection with rulerships of countries it may be noted that Brazil was named the Land of the Holy Cross by the discoverer Cabral on May 1st 1500, and that the constellation Crux has been represented on the postage stamps of that country. [Robson, p.41.]

References:

Fixed Stars and Constellations in Astrology, Vivian E. Robson, 1923].