Calcite with Malachite
Also known as Velvet Coral. They can be found in the shallow waters of the Indo-Pacific and Red Sea.
Graphic History of Architecture by John Mansbridge
Archaeologists working in Peru have discovered 25 well-preserved quipus, an ancient string-based device used to solve mathematical problems and to assist in record-keeping.
The find was made in the archaeological complex of Incahuasi, south of Lima, Alejandro Chu, reports Peru This Week. The items were found in ancient warehouses, or kallancas, and not in a funerary context as is the norm, making this a rather unique find. The placement of the quipus suggests they were used for administrative purposes. Incahuasi was one of the most important strategic cities built by the Incas in the valley of Lunahuana.
Quipu (also called “khipus” or “talking knots”) typically consisted of colored, spun, and plied thread or strings from llama or alpaca hair. They aided in data collection and record-keeping, including the monitoring of tax obligations, census records, calendrical information, and military organization. The cords contained numeric and other values encoded on knots in a base-10 positional system. Some quipu had as many as 2,000 cords.
Reflection - Odilon Redon
Hübnerite with Quartz and green Philipsburgite - Montana