Dark Magic is something that not many in the spiritualism community like to go into. In media we find that its often shunned to the side or seen as the more evil side of an otherwise love and light based system and it may be because of its negative depiction that many have a fear of preforming or teaching about the dark arts. I believe that this causes an imbalance in ones growth and wish to rectify this.
But before getting into it, a disclaimer. A spell of any kind is a tool. Despite Magic being an force of nature, tapping into this force for their own use comes with the implication that the user is aware and responsible for the end result, whatever that may be. The trigger for most magics is intention. This is why being aware of your thoughts is such a fundamental practice in spell work. This is not a lesson that is telling you to go out and hex your friends. This lesson exists to make you aware of the difference and give you one to practice / use.
You may have heard Hex, Curse, and Jinx used "almost" interchangeably. While confusing at first the three actually have a bit of a hierarchy and we can find it by looking at some of the inner workings of each spell type.
Starting with one of the lesser kinds of dark magics, a jinx/jynx is a spell that can sometimes go off unconsciously. It a jinx is created from such little magic it has such a low general detectability and can be created without even realizing it. This could be caused by pent up negative intentions or jealous thoughts that you haven't dealt with. When reminded of these sometimes you may unintentionally manifest unfortunate events or bad luck at targets, both intended and otherwise.
Luckily these types of spells can easily be removed by tuning, incense and candle magic. A basic, well tuned and upkept barrier will generally keep a jinx from affecting you.
A hex is a spell that is usually cast. Those with a higher skill level can sometimes reflexively cast hexes if the methods are met but in most cases the need for purpose and intense focus acts as a fairly reliable gateway to keep hexes from just spilling out from practitioners. Despite this however, hexes are the easier of the three to preform, requiring a basic ritual and perhaps a few magical items to preform. Hexes normally affect specific aspects of ones life. Their relationships, their job, or even their health.
A more adept barrier is needed to keep out hexes, and they can be removed using a ritual of equal or higher power.
These are the Big Baddies in the Dark Arts world and can be seen simply as a particularly powerful Hex. If you find that you are being afflicted by a curse know that someone has targeted you (or your family line / relation) directly. Curses are never unintentional and require all of the focus from a Hex as well as magical tools, a ritual, and special dark spells to employ specific problems in your life. There are strong intentions, negative emotions, and very specific spells woven into curses directed at a specific target that begin as a seed and seek to spread though the targets life.
A curse can penetrate most subconscious and conscious barriers and normally require a cleansing ritual of greater strength or a specific Curse breaking ritual. Spiritual Intervention is often a go to when looking to remove a curse as well.
Something to note: Though I haven't done too much research into it, many believe that each of the three stated spell types have a time restriction so to speak. A Jinx may last about a day or two and a hex can last anywhere from a few weeks to a few months. A curse will more than likely exist until removed which is one of the more dangerous parts of a curse.