http://book.klll.cc/ebooks/subject/27865.opds 2025-08-22T11:44:18Z Books about Gems -- United States (sorted by popularity) Free eBooks since 1971. Project Gutenberg https://book.klll.cc webmaster@gutenberg.org https://book.klll.cc/gutenberg/favicon.ico 25 1 2025-08-22T11:44:18Z https://book.klll.cc/ebooks/47999.opds Natural Gemstones Geological Survey