Physical and chemical properties
In purer forms, crack rocks appear as off-white nuggets with jagged edges, with a slightly higher density than candle wax. Purer forms of crack resemble a hard brittle plastic, in crystalline form (snaps when broken). A crack rock acts as a local anesthetic (see: cocaine), numbing the tongue or mouth only where directly placed. Purer forms of crack will sink in water or melt at the edges when near a flame (crack vaporizes at 90 °C, 194 °F).
Crack cocaine as sold on the streets may be adulterated or "cut" with other substances mimicking the appearance of crack cocaine to increase bulk. Use of toxic adulterants such as levamisole has been documented.
In order for cocaine (in plastic bag at bottom) to be converted to crack, several supplies are needed. Pictured here are baking soda
, a commonly used base in making crack, a metal spoon, a tealight
, and a cigarette lighter. The spoon is held over the heat source in order to "cook" the cocaine into crack.
A close up of the "cooking" process that creates crack.
Sodium bicarbonate (NaHCO3, common baking soda) is a base used in preparation of crack, although other weak bases may substitute for it. The net reaction when using sodium bicarbonate is
- Coc-H+Cl− + NaHCO3 → Coc + H2O + CO2 + NaCl
With Ammonium bicarbonate:
- Coc-H+Cl− + NH4HCO3 → Coc + NH4Cl + CO2 + H2O
With Ammonium carbonate:
- 2(Coc-H+Cl−) + (NH4)2CO3 → 2 Coc + 2 NH4Cl + CO2 + H2O
Crack cocaine is frequently purchased already in rock form, although it is not uncommon for some users to "wash up" or "cook" powder cocaine into crack themselves. This process is frequently done with baking soda (sodium bicarbonate), water, and a spoon. Once mixed and heated, the bicarbonate reacts with the hydrochloride of the powder cocaine, forming free base cocaine and carbonic acid (H2CO3) in a reversible acid-base reaction. The heating accelerates the degradation of carbonic acid into carbon dioxide (CO2) and water. Loss of CO2 prevents the reaction from reversing back to cocaine hydrochloride. Free base cocaine separates as an oily layer, floating on the top of the now leftover aqueous phase. It is at this point that the oil is picked up rapidly, usually with a pin or long thin object. This pulls the oil up and spins it, allowing air to set and dry the oil, and allows the maker to roll the oil into the rock-like shape.
Crack vaporizes near temperature 90 °C (194 °F), much lower than the cocaine hydrochloride melting point of 190 °C (374 °F). Whereas cocaine hydrochloride cannot be smoked (burns with no effect), crack cocaine when smoked allows for quick absorption into the blood stream, and reaches the brain in 8 seconds. Crack cocaine can also be injected intravenously with the same effect as powder cocaine. However, whereas powder cocaine dissolves in water, crack must be dissolved in an acidic solution such as lemon juice or white vinegar, a process that effectively reverses the original conversion of powder cocaine to crack.