Perlite, obsidian and pitchstone are volcanic glass having the same compositions commonly with rhyolite as well as andesite and basalt.

珍珠岩、黑耀岩和松脂岩等玻璃质熔岩以酸为主，者也常见。

The result indicated that transformation of perlite was accelerated and the quantities of ferrolites was increased under the function of impulse electric field at second stage graphitization.

进而分析了脉冲电作用下体石墨晶核的数,有效地缩短了珠光体分解时碳原子的扩散距离,从而速了第二阶段石墨化过程珠光体的转变。