[NTG-context] how to insert symbols into document?

Hello context users: I would like to insert symbols into my document, especially black-diamond and losenge symbols. I read symbols page at contextgarden but still don't know how to do it. I also tried \showsymbolset[was] etc but the symbols but I did not find these (and many other symbols either) in the output pages. I found that symb-imp-mis.mkiv file defines this symbol (line 49) but I don't know how to make it show. Do I have to load specific symbol fonts? If yes how can I find out which font has the given symbols? What I tried so far included: % begin code \usesymbols[imp-mis] \starttext ◆ \blackdiamond \symbol [blackdiamond] % end code None of these show anything. Thanks in advance, bcsikos