从植物学上，紫檀应为檀香紫檀一树种，可古玩界认为有两种性状稍有区别的紫檀木：有新、老之分，称,老者色赤，新者色红，放置时间长了即老，新鲜紫檀即为新紫檀。而实验证明，一种紫檀新伐材也不掉色，色素不具水溶性，心材紫红色，树生长稍大，挺直，空洞较少，这种紫檀新鲜剖面不是紫色，几近橘色,经久呈黑中带黄的颜色。称老紫檀；另一种木材从所谓老紫檀家具上拆下的，放在水中却有掉色的，色素具水溶性；心材橙红黄色，树小，扭曲，空洞多，剖面呈牛毛纹等，称新紫檀。原因是：由于生长条件不同，木材性状差异大。
紫檀树生长在润湿的气候下和土壤肥沃上，生长较好。呈常绿乔木、主干高15米以上，最大直径50厘米以上，一般直径20厘米左右。树干挺直，空洞较少，树皮黑褐色，深裂成长方形薄片，树液深红色。用手指敲原材端面有清脆的金属声。边材黄褐白色，心材紫红色，有非常美丽的黑色花纹，并有极细密的布格纹(波痕)。木质里含有丰富的紫檀素及油胶物质，纤维组织呈片状交叉状，管孔(棕眼)内充满亮晶晶的硅化物(侵填体)，油润坚重。含水率在12%时一般比重1.1以上，几乎不见棕眼，无蟹爪纹，细润得象光亮的塑料板。原材切开后，新鲜剖面有淡淡的酸香味，呈紫红色，无紫色，少有黑色花纹，经久，在阳光紫外线的作用下（非氧化）很快转为红葡萄酒带紫红色，呈现美丽的纹理，水泡不掉色，而酒精浸泡后则有紫色色素溶出，用端面在白纸上一划，便可留下紫红色痕迹。不易掉色是因木材油质多，色素不具水溶性。制成家具日久，油质重者呈深琥珀色，或称犀牛角色泽，触感也极似犀牛角样的坚硬、润滑、入手微温。所以有人称其为“犀牛角紫檀”。犀牛角紫檀制成的家具，色泽凝重，硬度高，特别是放置于空气中，被精心打磨的表面会形成包浆亮，颜色很快转成紫黑色，或紫中带红，或显深紫色，纹理深沉。木与木之间有比重、密度、颜色、油质多少，管孔内含物、粗细排列走向、花纹多少等等差异，同一株原木边材与心材也有密度和颜色上的差异。有的树管孔内多含红褐色树胶及和硅化物白色沉积物等侵填体，或受霉腐菌侵袭，致使部分管孔内沉积物病变发黄，剖面磨光后，管孔内发出闪亮光泽，故有人称“金星紫檀”。这一类紫檀产印度洋岛屿热带雨林，有所谓“海岛性紫檀”之说，俗称“老紫檀”，英文名：red sanders;red sandalwood。
紫檀树生长在干旱的气候下和脊薄的土壤上，为适应干旱的气候，长成落叶小乔木，大都呈灌木状，历经数百年甚至上千年长成小乔木，主干可高达5m以上，最大直径30cm以上，一般直径15cm左右，树干扭曲，少有平直。由于生长久远，空洞极多，有“十檀九空”之说。新鲜剖面有明显的蔷薇花香味，边材黄褐白色，心材橙红黄色，少有黑色花纹，有非常细密的布格纹(波痕)，木质里含有丰富的橙黄色素，新伐浅桔红，绝无紫色，新鲜剖面有淡淡的酸香味和明显的蔷薇花香味。在阳光紫外线的作用下转为紫红色。油质较少，所以色素具水溶性，比重1.01以上，纤维组织大都呈S状结构。管孔内硅化物较少，细密弯曲，极像牛背上的毛，所以被称作“牛毛紫檀”。心腐或空者管孔内黄红色沉积物极多，常具深或深紫黑色条纹，在阳光紫外线的作用下花纹增强加深，纹如蟹爪，扭曲飞动，犹如铸进去一般，极为美丽动人。制成家具日久，油质重者也呈深琥珀色，失蜡者呈灰褐色，清中后期紫檀家具均为此木种所制，相对来讲，存世量也较多。俗称：新紫檀、牛毛纹紫檀、花梨纹紫檀。新老紫檀都呈现金星，新紫檀也有“金星紫檀”之名，金星紫檀并非特殊木种。产中国南方周边旱季雨季分明的国家，即所谓“大陆性紫檀”。英文名：Burmacoast Padauk；amboyna；manilla padauk。古玩界有人把印度紫檀P.indicus（蔷薇木）与此种木材混淆。
管孔中至小或很小，管孔平均弦向径小于160μm，单个和2-10个(常2-4个)径、斜、团列，大小不一(有时生长轮开始处稍大，在一轮2/3处较小)，分布不均匀，含红褐色树胶或白色沉积物，木质里含有丰富的紫檀素及油胶物质，纤维组织呈片状交叉状，管孔(棕眼)内多充满亮晶晶的硅化物(侵填体)，油润坚重。木射线极细，单列为主，稍密，弦面放大镜下也不见，径面斑纹不明显；轴向薄壁组织带状（防管型、离管型），翼状及环管束状。生长轮不明显，若明显则由早材管孔大而少形成，带状薄壁组织所致。具波痕，有极细密的布格纹(波痕)。
木材可提取染料，含紫檀素(Santalin)。紫檀素溶于酒精或醚，木材煎汁显示荧光现象，具收敛消肿毒效能，削片、锯屑或磨汁供药用，常用作治疗毒疮。木材无滋味。纹理斜。结构细。耐磨。抗白蚁及其它害虫。具光泽，材色美丽。
可作珍贵家具、美术雕刻工艺品和镶嵌等用材。
檀香紫檀原产印度迈索尔邦、泰国、马来西亚、越南、缅甸及南洋群岛等地。台湾和广州栽培。《中国树木志》介绍：广州栽培60余年生，树高20m，胸径39.3cm，冠幅8.5m，耐干热气候，在高温45-46℃及低温7.2-12.7℃之间均能生长。
It is a large deciduous tree growing to 30–40 m tall, with a trunk up to 2 m diameter. The leaves are 12–22 cm long, pinnate, with 5–11 leaflets, the girth is 12-34 m wide. The flowers are produced in panicles 6–13 cm long containing a few to numerous flowers; flowering is from February to May in the Philippines, Borneo and the Malay peninsula. They are slightly fragrant and have yellow or orange-yellow petals. The fruit is a semiorbicular pod 2–3 cm diameter, surrounded by a flat 4–6 cm diameter membranaceous wing which aids dispersal by the water. It contains one or two seeds, and does not split open at maturity; it ripens within 4–6 years, and becomes purple when dry. The central part of the pod can be smooth (f. indica), bristly (f. echinatus (Pers.) Rojo) or intermediate.
Most Pterocarpus species prefer seasonal weather but P. indicus prefer rainforests.
Note: Pterocarpus macrocarpus, a similar species native to Burma, is referred to as "Rosewood" throughout South East Asia. P. macrocarpus, is usually harder than P. indicus. When in burl form both are referred to as Amboyna Burl.
Uses
Veneer with a shell-like grainThe hardwood, which is purplish, is termite resistant and rose-scented. The wood known in Indonesia as amboyna is the burl of the tree, named after Ambon, where much of this material was originally found. Often amboyna is finely sliced to produce an extremely decorative veneer, used for decoration and in making of furniture and keys on a marimba. The flower is used as a honey source while leaf infusions are used as shampoos. Both flowers and leaves were said to be eaten.The leaves are supposedly good for waxing and polishing brass and copper. The tree is recommended as an ornamental tree for avenues and is sometimes planted in Puerto Rico as a shade and ornament. It is also a source of kino or resin. In folk medicine, it is used to combat tumors. This property might be due to an acidic polypeptide found in its leaves that inhibited growth of Ehrlich ascites carcinoma cells by disruption of cell and nuclear membranes. It is also known as a diuretic in Europe during the 16th and 18th centuries. Its reputation may be due to its wood infusions, which are fluorescent. It is widely planted as a roadside, park, and car-park tree. The tall, dome-shaped crown, with long, drooping branches is very attractive and the flowers are spectacular in areas with a dry season. It is very easily propagated from seed or large stem cuttings, but suffers from disease problems.
Symbolism
It is the national tree of the Philippines, as well as the provincial tree of Chonburi and Phuket in Thailand.
