Pure boron is a dark solid at room temperature and when it has 11 neutrons can be turned into a powder and is used as an igniter for rocket fuel and it can be used in pyrotechnic flares. Boron can be mixed with sodium to make Borax (sodium borate) which is used to make eyedrops, washing powders, bleach, and food preservatives. Boron can also make Boric acid which is used to make a heat resistant glass that can be found in insulation. Boron mixes very well with water above 100°C to create most of its compounds. Boron with ten neutrons also has many uses which include treatment for some brain cancers and helping create control rods for nuclear reactors. Control rods are used in nuclear reactors to control the fission rate of uranium and plutonium.
Boron doesn't effect the human body too much if consumed in very small amounts but if you consume too much of it it can cause serious problems with your metabolism and how you digest food and can even poison you. Signs of poisoning include skin inflammation and peeling, irritability, tremors, weakness, headaches, depression, vomiting, and more.
Boron has three solid forms or allotropes. It can be a dark powder, a clear red crystal, and a black metallic looking crystal. Borons melting point varies depending on its allotrope but the melting range is between 2,200 and 2,300°C (4,000-4,200°F).