Chiastolite is a naturally occurring mineral, a form of Andalusite ( Al2SiO5 ), and is easily distinguishable by it’s black, cross shaped, inclusions of graphite. Most of the time it’s a brownish-gray in color, sometimes with dark red parts as well, and when cut in halves ( the natural specimens ) once can clearly see the cross pattern inside.
|Left: rough, "slabs" of Chiastolite, right polished tumbled stones|
The very name, originates from the Greek “chiastos” which means, “cross marked”,  and also “cruciform” or “crosswise”. It’s hardness on the Mohs’ scale is 6.5-7.5 , the strike is white, and the luster is vitreous. It can withstand high temperatures, without alteration, and is for this reason used high-temperature resistant ceramics and refractories. The faceted specimens exhibit the pleichroic effect ( “change” color depending on the angle from which they are observed ) and are for this reason valued among jewelers, and used in the jewelry. 
Use in magick
This auspicious natural talisman, has been used in healing and magick, for hundreds of years, already. It was believed to be a sign, or even gift from G’d, and it was, and still is, reverend as an amulet that negates curses and hexes. Today, it’s also frequently used to shield from, and fence off, psychic attacks. So it’s a powerful stone for spiritual protection, or, it’s a protective agent per excellence, especially against harmful magick.
|Charming Chiastolite crystal|
It is also a very spiritual stone, that both, uplifts spiritually, but grounds those that hold it, preventing that the spiritual experience gets the best of them. What more, it’s said to ground a spiritual experience, or insight, making it more understandable and permanent.
According to renowned author and crystal-therapist Judy Hall, the stone is a gateway to the mysteries as well. It facilitates astral projection, and helps people understand and explore the immortal nature of souls. It is related to death, and rebirth, and is believed to ease the transition of the soul form physical to other planes, thus helping those who are passing away. The stone can provide answers to mysterious events and occurrences. 
It’s an inspirational, and creative stone, which also boosts analytical faculties, and aptness in solving problems, which is connected to its use in crystal therapy.
It has the power to turn the conflict into harmony, and to dispel negative thoughts, sensations, and energy. That’s the majestic transformation power of the stone, to turn the negative into positive.
Additionally, it’s said to unite and draws elemental forces, due to the cross pattern, most likely, empowering thus spiritual work, and magickal rituals and spells.  This is why people sometimes place it on their altars.
It’s also seen as a stone of good luck, and is believed by many to be an amulet against the evil eye, or the glance of malice
It also has power to turn the calm confronted people, and turn conflict situations into more productive ones. Hence why it could be useful to carry to workplace , if the colleagues tend to argue.
Like any other stone/crystal/mineral , Chiastolite is also associated with planets, it “vibrates” with certain numerical value, and it channels energy, projecting or drawing it ( in this case, the stone is versatile, so it both receives and projects energies, equally well ), and here are some of the correspondences for the stone:
· * Planetary ruler: Various, Saturn
· *Elemental ruler: Various, or all the 4 classical elements
· *Numerical correspondence: 7
· * Energy: receptive and projective
· * Birthstone of: Libra and Virgo 
· * Time of year* : Samhain and Lammas
· *Angelic ruler: possibly ( ! )** Sandalphon or Cassiel
Use in crystal therapy
Chiastolite has relatively broad spectrum of “prescriptions” in regards of treating somatic and psychological aliments, and some of the suggestions are as follow:
“Healers use chiastolite to lessen fevers, rheumatism, balance the immune system, fortify nerves, and increase lactation in nursing mothers.” 
It’s also said to increase ability to solve problems, find different approaches and solutions to them , or to conquer them using analytical faculties, which the stone greatly enhances. It also dispels fear, illusions, and non-functional, old, thought-patterns. It reduces excess of acid in organism, and is said to be able to repair chromosome damages, and even treat paralysis. 
It’s empowers any chakra, if laid over it , and it’s extremely efficient in repairing auric damages, and filling up auric holes etc.
Spells and rituals
Dispel negative elements
Create an elixir with spring water and Chiastolite. Add to it few drops of Holy water, and a smallest pinch of salt. A drop of Camphor essential oil may be added as well, or a pinch of finely powdered / pulverized Vervain, If You feel so inclined, but it’s certainly not necessary
Now either put it in a spray bottle, and spray around the place that is disturbed with negative vibration, has “thick” air, or feels extremely “wrong” , or pour it into a ceramic lamp, light a candle and let it diffuse and dispel negative elements, replacing them with creativity and harmony.
Charm of spiritual aid
When someone is in dire need of spiritual assistance, of the benevolent spirits, due to some misfortune, trauma or illness, combine in a purple mojo bag:
· * Chiastolite
· * Aquamarine
· * Altaea roots, or Star Anise seeds
And dress the bag with “Spirit guide” or “Healing” condition oils. Any of the spiritual colognes, such as Florida water, or Kanaga water will also do just fine. Hold the bag in hands, light a white, purple or beeswax candle and pray, and ask the spirits to help. Leave the bag, alongside candle, glass of water and some fresh mint leaves on the altar until the candle burns all the way down.
Then the candle can be given to the person in question, or even slipped underneath their mattress, to draw help of kind spirits.
NOTE: This article was written and composed by myself, so If You wish to use any part of it elsewhere online, feel free, but add credits; Shadow of the Shadows magick place, Shadowfirstname.lastname@example.org or a direct link to this post
*While it’s only natural that certain gemstones take special place in certain magickal times, certain periods of the year, be it even a single day , it should be obvious that this does not imply that these stones can be used only in/on these given times. Crystals themselves are pretty much equally powerful all year long, If properly maintained ( cleaned and charged ), of course
** My own suggestion, I have not been able to found any association of the Cross stone, with any of the Angels or Archangels in the sources available to me. But the colors, shapes, properties of the Stone resonate with the two mentioned Archangels, strongly.
CREDITS AND REFERENCES:
 According to: https://crystal-cure.com/chiastolite.html
 More here: http://geology.com/minerals/andalusite.shtml
 “Crystal Bible; a definitive guide to crystals” by Judy Hall, 2005th edition
 According to the “Encyclopedia of crystal, gem and metal magic” by Scott Cunningham; pg. 87th Llewellyn publications
 Sources disagree; for example Gerina Dunwich, in her “Dunwich’s guide to gemstone sorcery” states it’s a Virgo birthstone, whereas http://www.healing-crystals-for-you.com/chiastolite.html ties it to the Libra
 Retrieved / quoted / cited from : https://crystal-cure.com/chiastolite.html for educational, explanatory and discussion purposes, without any ill will
 According to the source listed under 
Slabs of Chiastolite ( first image ) from
http://www.fossili.it/immaginiprodotti/andalusitegrezzo.JPG used here for illustrative and explanatory pruposes without any ill will
Thumbed Chiastolite from Crystal cure http://crystal-cure.com/pics/chiastolite-tum.jpg used here for illustrative and explanatory purposes without any ill will
The skull made from Chiastolite is from, http://www.skullis.com/ProductImage/4100124/Chiastolite-Crystal-Skull-03.jpg and is once again used for illustrative and explanatory purposes without any kind of ill will