Sandalwood is a class of woods from trees in the genus Santalum . The woods are heavy, yellow, and fine-grained, and, unlike many other aromatic woods, they retain their fragrance for decades. Sandalwood oil is extracted from the woods for use. Sandalwood is often cited as one of the most expensive woods in the world. Both the wood and the oil produce a distinctive fragrance that has been highly valued for centuries. Consequently, some species of these slow-growing trees have suffered over-harvesting in the past.
The nomenclature and the taxonomy of the genus are derived from this species' historical and widespread use. Etymologically it is ultimately derived from Sanskrit चन्दनं Chandana (čandana), meaning "wood for burning incense" and related to candrah, "shining, glowing" and the Latin candere, to shine or glow. It arrived in English via Late Greek, Medieval Latin and Old French in the 14th or 15th century.  The sandalwood is indigenous to the tropical belt of peninsular India, the Malay Archipelago and northern Australia   The main distribution is in the drier tropical regions of India and the Indonesian islands of Timor and Sumba.  
Sandalwoods are medium-sized hemiparasitic trees, and part of the same botanical family as European mistletoe. Sandalwood is indigenous to the tropical belt of the peninsular India, Malay Archipelago and northern Australia.   The main distribution is in the drier tropical regions of India and the Indonesian islands of Timor and Sumba.  It spread to other regions through the Incense trade route by the vast Indian and Arab mercantile networks and the Chinese maritime trade routes until the sixteenth century CE.  The sandalwood of peninsular India and Malay Archipelago supported most consumption in East Asia and West Asia during Incense trade route.   before the commercialization of sandalwood plantation ( Santalum spicatum ) in Australia and China. Although sandalwood album ( Santalum album ) is still considered to have the best and original quality in terms of religion and alternative medicine. Australian sandalwood ( Santalum spicatum ) is marketed as the notable members of this group today by merchants because of its stable sources; others in the genus also have fragrant wood. These are found in India, Nepal, Bangladesh, Pakistan, Sri Lanka, Australia, Indonesia, Hawaii, and other Pacific Islands,
Various unrelated plants with scented wood and also referred to as sandalwood, but not in the true sandalwood genus:
Producing commercially valuable sandalwood with high levels of fragrance oils requires Indian sandalwood ( S. album ) trees to be a minimum of 15 years old – the yield, quality and volume are still to be clearly understood. Yield of oil tends to vary depending on the age and location of the tree; usually, the older trees yield the highest oil content and quality. Australia is the largest producer of S. album, with the majority grown around Kununurra, in the far north of the state by Quintis (formerly Tropical Forestry Services), which in 2017 controlled around 80% of the world's supply of Indian sandalwood,  and Santanol.  India used to be the world's biggest producer, but it has been overtaken by Australia in the 21st century. Over-exploitation is partly to blame for the decline.  
Australian sandalwood ( S. spicatum ) is grown in commercial plantations throughout the wheatbelt of Western Australia, where it has been an important part of the economy since colonial times. As of 2020 [update] WA has the largest plantation resource in the world. 
Sandalwood is expensive compared to other types of woods. To maximize profit, sandalwood is harvested by removing the entire tree instead of felling at the trunk near ground level. This way wood from the stump and root, which possesses high levels of sandalwood oil, can also be processed and sold. 
Australian sandalwood is mostly harvested and sold in log form, graded for heartwood content. The species is unique in that the white sapwood does not require removal before distilling the oil. The logs are either processed to distill the essential oil, or made into powders for making incense. Indian sandalwood, used mainly for oil extraction, does require removal of the sapwood prior to distillation. As of 2020 [update] , Australian Sandalwood oil sells for around US$1,500 per 1 kilogram (2.2 lb), while Indian Sandalwood oil, due to its higher alpha santalol content, is priced at about US$2,500 per kg. 
Sandalwood is often cited as one of the most expensive woods in the world, along with African blackwood, pink ivory, agarwood and ebony.  
Sandalwood oil has a distinctive soft, warm, smooth, creamy, and milky precious-wood scent. Its quality and scent profile is greatly influenced by the age of the tree, location and the skill of the distiller. It imparts a long-lasting, woody base to perfumes from the oriental, woody, fougère, and chypre families, as well as a fixative to floral and citrus fragrances. When used in smaller proportions in a perfume, it acts as a fixative, enhancing the longevity of other, more volatile, materials in the composite. Sandalwood is also a key ingredient in the "floriental" (floral-ambery) fragrance family – when combined with white florals such as jasmine, ylang ylang, gardenia, plumeria, orange blossom, tuberose, etc.
Sandalwood oil in India is widely used in the cosmetic industry. The main source of true sandalwood, S. album, is a protected species, and demand for it cannot be met. Many species of plants are traded as "sandalwood". The genus Santalum has more than 19 species. Traders often accept oil from closely related species, as well as from unrelated plants such as West Indian sandalwood ( Amyris balsamifera ) in the family Rutaceae or bastard sandalwood (Myoporum sandwicense, Myoporaceae). However, most woods from these alternative sources lose their aroma within a few months or years.
Isobornyl cyclohexanol is a synthetic fragrance chemical produced as an alternative to the natural product.
Sandalwood's main components are the two isomers of santalol (about 75%). It is used in aromatherapy and to prepare soaps. 
Sandalwood lends itself well to carving and has thus, traditionally, been a wood of choice for statues and sculptures of Hindu Gods.
Due to its low fluorescence and optimal refractive index, sandalwood oil is often employed as an immersion oil within ultraviolet and fluorescence microscopy.
Aboriginal Australians eat the seed kernels, nuts, and fruit of local sandalwoods, such as the quandong ( S. acuminatum ).  Early Europeans in Australia used quandong in cooking damper by infusing it with its leaves, and in making jams, pies, and chutneys from the fruit.  In Scandinavia, pulverised bark from red sandalwood ( Pterocarpus soyauxii ) is used - with other tropical spices - when marinating anchovies and some types of pickled herring such as matjes , sprat, and certain types of traditional spegesild, inducing a reddish colour and slightly perfumed flavour.   
Present-day chefs have begun experimenting in using the nut as a substitute for macadamia nuts or a bush food substitute for almonds, hazelnuts, and others in Southeast Asian-styled cuisine.  The oil is also used as a flavour component in different food items, including candy, ice cream, baked food, puddings, alcoholic and nonalcoholic beverages, and gelatin. The flavouring is used at levels below 10 ppm, the highest possible level for use in food products being 90 ppm.
Oil is extracted from Sandalwood through distillation. Many different methods are used, including steam distillation, water distillation, CO2 extraction, and solvent extractions. Steam distillation is the most common method used by sandalwood companies. It occurs in a four-step process, incorporating boiling, steaming, condensation, and separation. Water is heated to high temperatures (60–100 °C or 140–212 °F) and is then passed through the wood. The oil is very tightly bound within the cellular structure of the wood, but can be released by the high heat of the steam. The mixture of steam and oil is then cooled and separated so that the essential oil can be collected. This process is much longer than any other essential oil's distillation, taking 14 to 36 hours to complete, but generally produces much higher quality oil. Water, or hydro, distillation is the more traditional method of sandalwood extraction which involves soaking the wood in water and then boiling it until the oil is released.  This method is not used as much anymore because of the high costs and time associated with heating large quantities of water. 
Sandalwood is very sacred in the Hindu Ayurveda and is known in Sanskrit as chandana.  The wood is used for worshipping the deities, and it is said that goddess Lakshmi lives in the sandalwood tree; therefore, it is also known as Srigandha. The wood of the tree is made into a paste by grinding sandalwood against stone slab, and this paste is integral to rituals and ceremonies, to make religious utensils, to decorate the icons of the deities, and to calm the mind during meditation and prayer. It is also distributed to devotees, who apply it to their foreheads or necks and chests.  Sandalwood paste is used for most pujas both in temples and home altars performed in private households.
The paste is prepared by grinding wood by hand against granite slabs shaped for this purpose. With the gradual addition of water, a thick paste forms (called kalabham "കളഭം" in Malayalam language and gandha ಗಂಧ in Kannada) and is mixed with saffron or other such pigments to make chandanam. Chandanam, further mixed with herbs, perfumes, pigments, and some other compounds, results in javadhu. Kalabham, chandanam, and javadhu are dried and used as kalabham powder, chandanam powder, and javadhu powder, respectively. Chandanam powder is very popular in India and is also used in Nepal. In Tirupati after religious tonsure, sandalwood paste is applied to protect the skin. In Hinduism and Ayurveda, sandalwood is thought to bring one closer to the divine. Thus, it is one of the most used holy elements in Hindu and Vedic societies.  
Sandalwood use is an integral part of daily practices of Jainism. Sandalwood paste mixed with saffron is used to worship tirthankar Jain deities. Sandalwood powder is showered as blessings by Jain monks and nuns (sadhus and sadhvis) to their disciples and followers. Sandalwood garlands are used to dress the body during Jain cremation ceremonies. During the festival of Mahamastakabhisheka that is held once in every 12 years, the statue of Gommateshwara is then bathed and anointed with libations such as milk, sugarcane juice, and saffron paste, and sprinkled with powders of sandalwood, turmeric, and vermilion. 
Sandalwood is mentioned in various suttas of the Pāli Canon.  In some Buddhist traditions, sandalwood is considered to be of the padma (lotus) group and attributed to Amitabha Buddha. Sandalwood scent is believed by some to transform one's desires and maintain a person's alertness while in meditation. It is also one of the most popular scents used when offering incense to the Buddha and the guru.
In sufi tradition, sandalwood paste is applied on the sufi’s grave by the disciples as a mark of devotion. The tradition is borrowed from indian rituals and is practiced particularly among the Indian Subcontinent disciples. In the Tamil culture irrespective of religious identity, sandalwood paste or powder is applied to the graves of sufis as a mark of devotion and respect.   
In East Asia, sandalwood (檀木), is the most commonly used incense material by the Chinese, Korean and Japanese in worship and various ceremonies. However, some sects of Taoists, following the Ming Dynasty Taoist Manual, do not use lakawood but sandalwood (as well as benzoin resin, frankincense, foreign produced) incense, in worship.  In Korean Shamanism, sandalwood is considered the Tree of Life. It was trasmitted to China, the Korean Peninsula, and Japan during the eastward expansion of Buddhism.  : 3
Zoroastrians offer sandalwood twigs to the afarganyu, the urn in which the fire is kept at the fire temple (called agiyari in Gujarati and dar-e mehr in Persian), to keep the fire burning during religious ceremonies. After the firekeeping priests complete the ceremony, attendees are allowed to come up to the afarganyu and place their own pieces of sandalwood into the fire. Fire has been a sacred symbol in the Zoroastrian religion since ancient times and it is considered very important to keep the fires in the temples constantly burning. Because of its high sensitivity to fire, sandalwood works very well for this. Also, the wood has been accepted by the Yasna and Yashts as an appropriate fuel for the fire. It is offered to all of the three grades of fire in the fire temple, including the Atash Dadgahs. Sandalwood is not offered to the divo, a smaller lamp that is kept in the homes of Zoroastrians. Often, money is offered to the mobad (for religious expenditures) along with the sandalwood. Sandalwood is called sukhad in the Zoroastrian community. The sandalwood in the fire temple is often more expensive to buy than at a Zoroastrian store. It is often a source of income for the fire temple.[ citation needed ]
Incense is aromatic biotic material that releases fragrant smoke when burnt. The term is used for either the material or the aroma. Incense is used for aesthetic reasons, religious worship, aromatherapy, meditation, and ceremony. It may also be used as a simple deodorant or insect repellent.
Santalum is a genus of woody flowering plants in the Santalaceae family, the best known and commercially valuable of which is the Indian sandalwood tree, S. album. Members of the genus are trees or shrubs. Most are root parasites which photosynthesize their own food, but tap the roots of other species for water and inorganic nutrients. Several species, most notably S. album, produce highly aromatic wood, used for scents and perfumes and for herbal medicine. About 25 known species range across the Indomalayan, Australasian, and Oceanian realms, from India through Malesia to the Pacific Islands, as far as Hawaiʻi and the Juan Fernández Islands off the coast of South America.
Agarwood, aloeswood, eaglewood or gharuwood is a fragrant dark resinous wood used in incense, perfume, and small carvings. This resinous wood is most commonly referred to as oud or oudh. It is formed in the heartwood of aquilaria trees when they become infected with a type of mold and secretes a resin to combat the mold. Prior to infection, the heartwood is odourless, relatively light and pale coloured; however, as the infection progresses, the tree produces a dark aromatic resin, called aloes or agar as well as gaharu, jinko, oud, or oodhaguru, in response to the attack, which results in a very dense, dark, resin-embedded heartwood. The resin-embedded wood is valued in East and South Asian cultures for its distinctive fragrance, and thus is used for incense and perfumes.
Santalum acuminatum, the desert quandong, is a hemiparasitic plant in the sandalwood family, Santalaceae, which is widely dispersed throughout the central deserts and southern areas of Australia. The species, especially its edible fruit, is also commonly referred to as quandong or native peach. The use of the fruit as an exotic flavouring, one of the best known bush tucker, has led to the attempted domestication of the species.
Santalum spicatum, the Australian sandalwood, also Waang and other names (Noongar) and Dutjahn (Martu), is a tree native to semi-arid areas at the edge of Southwest Australia, in the state of Western Australia. It is also found in South Australia, where it is protected and listed as a vulnerable species. It is traded as sandalwood, and its sandalwood oil has been used as an aromatic and a food source over history. S. spicatum is one of four Santalum species occurring in Australia.
The burning of incense in Japan began during the 6th century with the introduction of Buddhism, which uses incense during rituals and ceremonies. Agarwood was imported into Japan from China via Korea. From that point on, incense would become an important facet of Japanese culture. Incense is used for a variety of purposes, including Buddhist ceremonies, spirituality and meditation.
In India, incense sticks, called Agarbatti ,) are a large part of the economy and many religions in the region.
Hedychium spicatum is a plant species native to China, the Himalayas, Myanmar, Thailand and Ethiopia.
Santalum album, or Indian sandalwood, is a small tropical tree, and the traditional source of sandalwood oil. It is native to southern India and Southeast Asia. It is considered sacred in some religions like Hinduism, and some cultures place great significance on its fragrant qualities. However, the high value of the species has caused over-exploitation, to the point where the wild population is vulnerable to extinction. Indian sandalwood still commands high prices for its essential oil owing to its high alpha santalol content, but due to lack of sizable trees it is no longer used for fine woodworking as before. The plant is long-lived, but harvest is only viable after many years.
Ittar, also known as attar, is an essential oil derived from botanical or other natural sources. Most commonly these oils are extracted via hydro or steam distillation. The Persian physician Ibn Sina was first to derive the attar of flowers from distillation. Attar can also be expressed by chemical means but generally natural perfumes which qualify as ittars are distilled with water. The oils are generally distilled into a wood base such as sandalwood and then aged. The aging period can last from one to ten years depending on the botanicals used and the results desired. Technically ittars are distillates of flowers, herbs, spices and other natural materials such as baked soil over sandalwood oil/liquid paraffins using hydrodistillation technique involving a still and receiving vessel. These techniques are still in use today at Kannauj in India.
β-Santalol is an organic compound that is classified as a sesquiterpene. It comprises about 20% of the oil of sandalwood, the major component being α-santalol. In 2002, about 60 tons of sandalwood oil were produced by steam distillation of the heartwood of Santalum album.
α-Santalol, also referred to as alpha-santalol, is an organic compound that is classified as a sesquiterpene. It comprises about 55% of the oil of sandalwood, another less abundant component being β-santalol. As of 2002, about 60 tons of sandalwood oil are produced annually by steam distillation of the heartwood of Santalum album. It is a valued component for perfumes.
Incense in China is traditionally used in a wide range of Chinese cultural activities including religious ceremonies, ancestor veneration, traditional medicine, and in daily life. Known as xiang, incense was used by the Chinese cultures starting from Neolithic times with it coming to greater prominence starting from the Xia, Shang, and Zhou dynasties.
Sandalwood is the common name of many species of plants and their wood and oils.
Sandalwood oil is an essential oil obtained from the steam distillation of chips and billets cut from the heartwood of various species of sandalwood trees, mainly Santalum album and Santalum spicatum.
Santalum freycinetianum, the forest sandalwood, Freycinet sandalwood, or ʻIliahi, is a species of flowering tree in the European mistletoe family, Santalaceae, that is endemic to the Hawaiian Islands. Its binomial name commemorates Henri Louis Claude de Saulces de Freycinet, a 19th-century French explorer. ʻIliahi inhabits dry, coastal mesic, mixed mesic, and wet forests on Oʻahu, Kauaʻi, Lānaʻi, Maui, and Molokaʻi at elevations of 250–950 m (820–3,120 ft). It grows in areas that receive 500–3,800 mm (20–150 in) of annual rainfall. Like other members of its genus, ʻiliahi is a root hemi-parasite, deriving some of its nutrients from the host plant; common hosts include koa, koaiʻa, and ʻaʻaliʻi.
Sesbania rostrata is a small semi-aquatic leguminous tree, in the genus Sesbania. It forms a symbiotic relationship with Gram-negative rhizobia which leads to the formation of nitrogen fixing nodules on both stem and roots. It is mainly used as green manure to improve soil fertility due to its fast growth, high biomass production and ability to convert large amounts of atmospheric nitrogen into a usable form for plants. Other applications include production of high quality forage for livestock and it is a source of fuel-wood.
Osyris daruma is a species of plant in the family Santalaceae.
Mysore Sandalwood Oil is a trademarked perfume oil extracted from the Santalum album variety of sandalwood tree in the Mysore district of Karnataka, India. The tree species is said to be one of the best varieties in the world.
Albizia procera, commonly known as white siris or karoi tree, is a species of large tree found natively in southeast Asia and India. It is most commonly found in open forests, but may also be found on the margins of rain forests and in monsoon and gallery forests. It is considered an invasive species in South Africa.