1.5g of cocaine ain't shit in all honesty.. at the end of a night of coke use one could do that much in a couple lines over just a few minutes..
Lots of things though... first, the coke is cut - but by how much? I had a roomate that found a cut which wiuld number the user MORE then the actuall cocaine would, so, he would cut by about 300% - ie a "gram" of coke from his consisted of .25g of coke and .75g of cut ..
Some people also simply dont react for shit to the drug - I have to rail close to 1/4thg for any noticible effect...
Sorry, this is why we dont allow dose threads, ESPECIALLY with a drug like cocaine, where you have NO IDEA how much cocaine you're actually taking....
My advice (I give this to everyone that asks about doses) - start small, like a decent size line.. wait a few minutes, if you're not happy - do more!