Here is a list of different forms of incense, this list is generalized and by no means exhaustive.

Senko
Senko is a basically a solid stick, with no core. These sticks are usually very dry, and thin. Length varies. The base is usually of a wooden powder, most commonly sandalwood, although other woods are used too, like agarwood. The mixtures can be simple, with one or two ingredients, to complex, with a long list of ingredients. This style is usually seen in Japanese, Korean, and sometimes Chinese incense.

Rope/String Incense
Rope or string incense consists of fragrant herbs and woods. A powdered mix is wrapped in  a slow burning paper, like rice or lakota, and then twisted into a rope. Although this may seem simple, perfecting a pleasing fragrant formula takes talent and know how. Some recipes are very old, and some contain plants that may only grow in specific regions, and ingredient flammability is also a concern. Recipes, just as in any incense mixture, must have exact measurements in order for the same fragrance to be obtained each time. The Himalayans, Tibet, Bhutan, and Nepal are some of the areas that produce a large amount of the rope incense on the current market. A good number of  rope incense is made of natural materials. Some ingredients  you may see in a rope incense, but is not limited to, are: nagi, sandalwood,red sandalwood, sweet flag,costus, saffron, sang, cedar, white sandalwood, juniper,gum-guggul,spikenard,jasmine, saldhoop,kumkum,gokul,frankincense,yellow sandalwood, and ghee (butter).*A few times I have seen cotton string, sometimes organic, sold. It actually does not have solid incense inside, but is a twisted string soaked in essential oil or fragrance oil. I have only seen this by independent American craftsmen. I have not tried these personally, but I heard that they have potential.

Loose Incense/Resin Mix Incense
Loose or resin mix incense is probably the earliest forms of actual incense recipes. Before, incense was probably just fragrant wood or a pleasing resin laid on a fire. At some point in history, someone got the idea that if you burn this resin with this resin, herb and/or wood, then the aromas would compliment each other. Loose incense is still used today, some churches still place resin mixes in burners during services, temples, and the individual consumer does as well. This type of incense is usually placed on a burner, or on charcoal. There are burners that have a deeper bowl for a piece of charcoal, and a screen above for the mixture to be heated slowly, instead of burned. In today’s market are also electric burners, heated to an exact temperature so it puts out scent but will not scorch the incense, some of the models out can also be used to burn other forms of incense like oils and bakhoors. Some makers of incense offer high quality loose incense, however a person at home can also make their own loose incense mixtures . Some mixes you can buy are intended for religious use, some mixes that are available for sell are made by master crafters of incense, with rare woods and oils. Ingredients that may commonly be in loose incense mixes are: most if not all types of sandalwood, frankincense, myrrh, amber resins, various tree gums, agarwood/aloeswood, rose petals, essential oils, cedar, patchouli plant/oil, dragons blood, copal, white sage, sage, lemongrass, sweet grass, sweet flag, orris root, oakmoss, lavender. honey, benzoin,cinnamon, clove, cardamom pods/seeds,jasmine, evergreens,citrus,olibanum, breuzinho, galbanum, labdanum, opoponax,Palo Santo, rosewood, and elemi. This type of incense is not really restricted or limited to one area. Places that may sell a little more commonly loose or resin mix incense are the Americas, throughout Europe, and India.

Cone Incense
Incense that is powdered,and is flammable on its own (with out the aid of a wooden core) can be formed into cones. Cone incense is common on the incense market, and can range from a low quality synthetic base to a high quality fragrant wood/resin base. Ingredients in cone incense are vast, some are charcoal soaked or dipped in fragrance oils, a few are a little better and the oils used are natural essential, or absolutes. Wooden base cones are frequent too, using sandalwood, cedar, makko (common ingredient in incense to make it flammable naturally) or even aloeswood. The cone style of incense is made by large number of different cultures and countries, a few would be North and South America, Thailand, India, China and Japan.

Kneaded/Pellet Incense
This type of incense is similar to powdered incense, the difference being that the powdered incense is made moist, sometimes set overnight in a liquid, and kneaded into little pellets. Once these dry or “cure”, they are placed on a burner like loose incense and are enjoyed. Just like any incense, the recipes can consist of a scant few ingredients to a plethora of materials. Not only is a liquid added to make the mixture easier to sculpt, some times soft resinous semi liquids are used to help hold the rounded shape, and to add scent. Honey, labdanum, benzoin, galbanum, molasses, oakmoss absolute, storax/liquid amber,liquid balsam, peru balsam and sometimes the meat of fruits (like raisins) are just a few. Wine is occasionally incorporated into the recipes as well. Kneaded incense is offered by some Japanese companies, and by smaller western ones. Neriko/Awaseko Neriko’s are a form of kneaded incense in Japan. They are also made of aromatic, natural ingredients, such as woods, powders,resins etc. The meat of plums, honey or labdanum is mixed in to help form it usually.

Powdered Incense
Powdered incense is another incense that was possibly used earlier in history. Powdered incense can be a one ingredient substance, or it can consist of fifty or more materials. Powdered sandalwood is a common incense by itself, or it can be mixed with other dry botanicals. Generally powdered incense is all natural, sometimes oils are added, usually natural also, but the powder is used when it is dry. Some ingredients you may come across in this type is sandalwood, cedar, agarwood, ambers, resins, juniper, and sage. Japan, Korea, the America’s, India, Tibet and Nepal is just the tip of the iceberg when looking for cultures that consistently make powdered incense.
Powder/Incense Trails  These are made by making a line, and then lighting one end, and the incense burns in the shape/line that you created. Sometimes the powder is already flammable, it easily burns, and sometimes a flammable su

Cored or Stick Incense
Ah,  where do I start. Stick incense is made just about anywhere, you name it, they probably make it. China,the Americas, Spain/Europe, Thailand, India, Tibet, the Bhutan, Nepal,and France. However, there are variations in stick incense.
Charcoal Based Sticks Charcoal is used for its flammability and it holds oils well. There’s natural charcoal, then there’s not so natural charcoal.  Punks are charcoal sticks that are unscented and usually have a chemical added to make it burn. These are not intended for incense actually, but for fireworks. Unfortunately, some companies have found that these “punks” are incredibly cheap, so they purchase them, and dip/soak them in fragrance oil. These are usually behind the headaches you hear about when someones states ” I can’t use incense, it gives me a headache”. Not all charcoal incense are bad, or full of toxic components. There are sticks that use clean charcoal, and the oils that are used are usually natural or at least a high quality synthetic. There are still some people who still don’t like charcoal based incense, there is a odor that it emits from the charcoal itself that is unpleasant to some.
Masala Based Sticks Masala roughly means mix.These types of stick incense are considered better as far as quality, although there are some that are made with poor fragrance (synthetic) oils, and chemicals added to make it easier to burn. Generally decent quality masala’s are made by starting out with a batter, consisting of natural woods, resins and oils, then the mixture is kneaded, sometimes set out to blend for a certain amount of time and then a skilled craftsmen rolls out the fragrant dough, and rolls pieces of it on a stick. If you ever see someone do this, they usually do this with speed, and it may look simple, it isn’t. Adding the right amount of the mixture to each stick and applying the correct pressure is important for a incense that burns evenly.Then the stick is dusted with a wood powder, like sandalwood to round it out. And skill is needed for the masala recipe, showing that even the smallest incense producers are talented craftspeople. When a masala based incense contains a lot of oil, and it appears moist, this is a called a wet masala. When it appears just a little moist, it has a little less oil, and is called semi wet masala. And when it feels and looks dry, it has even less oil, and is called dry masala. Good quality nag champa incense’s are usually masala, and the even higher quality ones are at semi wet to wet, the oil being halmaddi ( most champa’s do not contain as much of this oil as they previously did due to current availability and price).Sometimes you may come across a stick that is mixed between a masala and charcoal, these generally are dry. The quality of these vary.

Dhoop
Dhoop is incense without a core. It;s meaning and use is rather loose, it describes more than one type of incense. Senko and cones can be described as a form of dhoop. Dhoop can be dry and easily breakable sticks, short cones, or moist resinous logs. They can use natural materials and ingredients, or some smell suspiciously like burning rubber. Most Tibetan style incense is described as dhoop. The majority of regions that produce incense, make some form of dhoop also. Some of the producers and companies are based out of Japan, China, Korea, India, Tibet, the Bhutan, Nepal, the Middle East, and the America’s.

Bakhoors/Bukhoors/Resin Cakes and Bricks
Bakhoors and resin cakes are not necessarily the same, but the both are solid brick like incense. Bakhoor’ s come out of Arabia and the Middle East. Occasional a bakhoor brick is charcoal based, but mostly they are made of highly fragrant wood and perfumes/oils. A common ingredient is agarwood or it’s oil, oudh. Rose and other floral oils can also be an ingredient in a bakhoor, so can true musk. Instead of the bakhoor being a brick, it can also just be woodchips soaked in aromatic oils. Resin cakes/bricks are not something that you may really stumble across in the incense market, basically they are kneaded incense, but instead of being in the form of pellets they are molded into cake or brick like shapes.

Coil Incense
In the same spirit as dhoop and similar in dryness as senko, are solid direct burning  coils. Like most incense this is not strictly limited to one region, but you are more likely to see it made and used in Asia.  In China you can see and smell long coils burning in the streets during festivals, and coils are hung at shrines and temples in Japan. Smaller coils are usely for personal enjoyment, burning about thirty minutes and larger ones may also be for the home, larger ones for larger rooms. In the size range you will find medium coils that burn around two hours to eight hours on larger ones, to twenty four hours  on the much larger ones.  Ingredients you may see frequently are, sandalwood, star anise, clove, cassia, benzoin, and agarwood. There of course some much more you can include as an ingredient, those are just few your nose may encounter.

To be completed soon!