Many of the surfaces of a large industrial scale wine press from the Byzantine period in Yavne, Israel, are covered in mosaic tesserae. These surfaces are part of the grape presses, storage pools, fermentation pools and also the walkways between these structures. The calcitic tesserae resemble limestone in color, texture and fracture properties. We were therefore surprised to discover that they are more disordered at the atomic level than consolidated limestone and in fact they are as disordered as porous and friable chalk. In addition SEM examination of fracture surfaces reveals abundant nannofossils, mostly coccoliths and foraminifera; properties that are also reminiscent of chalk. The nanofossil identifications shows that the tesserae are from the Middle Eocene, and this includes the chalky Maresha Formation that outcrops about 15kms from the site. SEM examination of polished surfaces shows that the larger pores of tesserae are lined with euhedral calcite crystals. Vickers hardness measurements show that the tesserae are much harder than chalk, and are comparable to limestone. There are two scenarios for explaining these seemingly contradictory observations. One scenario is that a chalky limestone geological formation with all these properties exists somewhere in the Mediterranean region and is the source of the raw material for the tesserae. The second scenario is that the Byzantine constructors of the wine press transformed a chalk into a harder and more consolidated material. Chalk transformation processes akin to plaster formation can be excluded based on the analyses of the stable carbon isotopic compositions of the tesserae, as well as their ¹⁴C concentrations. A chemical transformation using a weak acid that would only affect the calcite in the vicinity of the accessible pores, and leave the bulk of the chalk and its microfossils in a good state of preservation, is conceivable. In fact a by-product of producing wine is vinegar and the acetic acid of the vinegar could conceivably have been used for this purpose. If indeed a chemical transformation of soft chalk into a hard durable material was used, this would represent a “lost” technology that might even be useful in present times.

以色列亚夫内拜占庭时期的大型工业压榨机的许多表面都覆盖着马赛克镶嵌物。这些表面是葡萄压榨机、储存池、发酵池以及这些结构之间的走道的一部分。方解石镶嵌物的颜色、质地和断裂特性与石灰石相似。因此，我们惊讶地发现它们在原子水平上比固结石灰石更加无序，事实上它们与多孔且易碎的白垩一样无序。此外，断口扫描电镜检查显示出丰富的超微化石，主要是颗石虫和有孔虫；其特性也让人想起粉笔。纳米化石鉴定表明，镶嵌物来自中始新世，其中包括距该地点约 15 公里处露头的白垩质 Maresha 地层。抛光表面的 SEM 检查表明，镶嵌物的较大孔隙内衬有自形方解石晶体。维氏硬度测量表明，镶嵌物比白垩硬得多，与石灰石相当。有两种情况可以解释这些看似矛盾的观察结果。一种情况是，具有所有这些特性的白垩石灰岩地质构造存在于地中海地区的某个地方，并且是镶嵌物的原材料的来源。第二种情况是，拜占庭的葡萄酒压榨机建造者将粉笔变成了更坚硬、更坚固的材料。根据对镶嵌物的稳定碳同位素组成及其¹⁴ C 浓度的分析，可以排除类似于石膏形成的白垩转化过程。可以想象，使用弱酸进行的化学转化只会影响可进入孔隙附近的方解石，并使大部分白垩及其微化石处于良好的保存状态。事实上，生产葡萄酒的副产品是醋，可以想象，醋中的乙酸可用于此目的。如果确实使用软粉笔化学转化为坚硬耐用的材料，这将代表一种“失落”的技术，甚至在当今时代可能有用。