出典:Wiktionary
出典:Wikipedia
出典:『Wikipedia』 (2011/04/18 20:50 UTC 版)
Apache tears are rounded nodules of obsidian (volcanic black glass) with diameter from about 0.5 to 5 cm. An Apache tear looks opaque by reflected light, but translucent when held up to light. Apache tears are usually black, but can range from black to red to brown. They are often found embedded in a greyish-white perlite matrix.