{
	"material":[
		{
			"id":"33",
			"term":"Tin or tin alloy",
			"bmID":"11849",
			"termdesc":"<p>In theory, use for tin, or for alloys where you suspect that the major ingredient is tin.  In practice, tin as a primary material is pretty much impossible to tell from lead, and as a coating is not possible to tell from silver (use \u2018white metal\u2019 in these circumstances).  Relatively pure tin with a little hardening alloy added (e.g. post-medieval pewter or Britannia metal) tends to crystallise in the soil and form delaminating layers or cuboidal blocks, so you can safely use \u2018tin or tin alloy\u2019 for these, with the words \u2018pewter\u2019 or \u2018Britannia metal\u2019 in the Description field if desired.  Use \u2018tin or tin alloy\u2019 for certain 17th-century coins which are known to be made from tin, although these will generally be too late to be worth recording.<\/p>",
			"parentID":"1",
			"valid":"1",
			"timestamp":"2013-07-18 09:07:40",
			"created":"2003-04-01 12:00:00",
			"createdBy":"1",
			"updated":"2010-07-09 14:14:48",
			"updatedBy":"19"
		}
	]
}