Kogumi:
A projectile point of quartz crystal, a rarity for the entire nation, is recovered. A large-scale production site is found.

Unfinished projectile point This item is thought to have broken in two during the process of manufacturing a projectile point. It tells the difficulty of making finished products from quartz crystal, an extremely hard material. Length: 3.9 cm.	Fluted projectile point The thinly-flaked cross section of the tip of one end has a trough-like depression, a characteristic known as fluted flaking. The fluted end has an indented outline, classifying it as the Higashiuchino type. Length: 5.8 cm.
Piece of raw quartz crystal Length: 8.2 cm.	Stone core Length: 5.9 cm.
	Stone tool refitted with flaked-off material Width: 17.2 cm.
Diagram of stone tool discoveries Adapted from Hakkutsu sareta Nihon rettō 2007 [Excavations in the Japanese Archipelago, 2007] (Bunkachō [Agency for Cultural Affairs], ed., Asahi Shimbunsha, 2007).	Stone tool concentration No. 1 Ninety percent of the quartz crystal stone items were recovered from the stone tool concentration at Locale No. 1. Photo shows the condition in which they were discovered. The white items are quartz crystal stone tools.

Kogumi Site, Kasama City, Ibaraki Prefecture

Concentrations of quartz crystal stone tools are recovered

In two excavations conducted in fiscal 2002 and 2004, eight locales with concentrations of stone tools were discovered on a gentle slope at the base of a hill, at intervals along a contour line 38 m in elevation. The total number of quartz crystal stone items recovered was 2,255, ranging stratigraphically from transitional to soft loam layers, with the distribution centered within the soft loam layer. Although it is difficult to discern key strata (volcanic ash strata that can serve to index chronological age) in Ibaraki because it is the area within the Kanto region where the loam is thinnest, from comparisons with adjacent districts and examinations of the shape of each stone tool, the quartz crystal artifacts are known to date from the latter half of the Upper Paleolithic.

Locales where projectile points were made

From Locale No. 1, one of the eight concentrations of stone tools, there were 1,977 items recovered, roughly equal to 90 percent of all of the quartz crystal artifacts. These items include projectile points used as spear heads, pieces of raw quartz crystal, large pebble flakes made just by roughly fracturing the raw quartz, and cores from which flakes as raw materials for tools had been taken. In addition, minute chips produced when finishing projectile points were found in large quantities, and it is understood that the entire process of stone tool manufacture, going from the raw material to the final product, was conducted.

From an analysis of the recovered stone tools, two types of projectile points are seen: those made directly from large stones of quartz crystal, and those made from flakes taken off such stones. Also, right beside this concentration of stone tools at Locale No. 1 is another, Locale No. 2, where round cobblestones of chert, hornfels, andesite and so forth were discovered. These are thought to have been the hammer stones and anvil stones used in the task of splitting the quartz crystal.

Stone toolmakers who strongly preferred quartz crystal

When manufacturing tools from stone, not any type of stone will serve as the raw material. It is thought that in the Paleolithic period, the ease with which the stone could be worked, together with the ease of use after completion of the tool, were among the criteria considered important, and it appears that materials such as obsidian, shale, andesite were mainly utilized. Projectile points of andesite were indeed recovered from the stone tool concentration at Locale No. 1. What was the reason, then, for the deliberate selection of a material not meeting these criteria: quartz crystal, which is hard and not suited to stone tool manufacture? One answer lies in its ease of procurement. From the recovery of raw material and numerous stone cores of quartz crystal at the Kogumi site, and from the rounded condition of the stones serving as raw material, it is thought that quartz crystal was gathered from a riverbed nearby the site.

But possibly there was some reason other than ease of procurement. The answer may lie surprisingly enough in the very brilliance of the stone tools, seemingly transparent, made from quartz crystal. Whatever the reason, traces of concentrated manufacture in large numbers of quartz crystal stone tools are rare even when looking on a nationwide basis, and their discovery can be said of great value for considering trends of Paleolithic man with regards to stone tool materials. (Hayakawa Reiji)