{"product_id":"lodestone-f4767-001","title":"Lodestone","description":"The lodestone, a piece of magnetite, which is naturally magnetic, was vital in the early centuries of navigation to ensure that the ship's compass worked properly. Until the mid-18th century, when improved compasses were developed, compass needles lost their magnetism quite quickly and had to be re-magnetised by stroking a lodestone along the needle's length.\u003cbr\u003e\u003cbr\u003eLodestones were often mounted in frames of brass, bronze or silver, and sometimes had an iron or steel keeper, a bar to help preserve their magnetic power. This lodestone has a brass frame with a carrying loop on top, and is 'armed' with two pieces of steel at the bottom, which help to increase the magnetic strength of the lodestone.","brand":"prodigi","offers":[{"title":"Fine art poster \/ XS: 30 x 30cm \/ none","offer_id":57010578588030,"sku":"GLOBAL-FAP-12X12","price":22.95,"currency_code":"GBP","in_stock":true},{"title":"Fine art poster \/ S: 40 x 40cm \/ none","offer_id":57010578620798,"sku":"GLOBAL-FAP-16X16","price":28.95,"currency_code":"GBP","in_stock":true},{"title":"Fine art poster \/ M: 50 x 50cm \/ none","offer_id":57010578653566,"sku":"GLOBAL-FAP-20X20","price":38.95,"currency_code":"GBP","in_stock":true},{"title":"Fine art poster \/ L: 70 x 70cm \/ none","offer_id":57010578686334,"sku":"GLOBAL-FAP-28X28","price":54.95,"currency_code":"GBP","in_stock":true},{"title":"Fine art poster \/ XL: 80 x 80cm \/ none","offer_id":57010578719102,"sku":"GLOBAL-FAP-32X32","price":69.95,"currency_code":"GBP","in_stock":true},{"title":"Fine art poster \/ XXL: 100 x 100cm \/ none","offer_id":57010578751870,"sku":"GLOBAL-FAP-40X40","price":82.95,"currency_code":"GBP","in_stock":true},{"title":"Framed picture \/ XS: 30 x 30cm \/ none","offer_id":57010578784638,"sku":"MUS-CFPM-12X12","price":59.95,"currency_code":"GBP","in_stock":true},{"title":"Framed picture \/ S: 40 x 40cm \/ none","offer_id":57010578817406,"sku":"MUS-CFPM-16X16","price":79.95,"currency_code":"GBP","in_stock":true},{"title":"Framed picture \/ M: 50 x 50cm \/ none","offer_id":57010578850174,"sku":"MUS-CFPM-20X20","price":119.95,"currency_code":"GBP","in_stock":true},{"title":"Framed picture \/ L: 70 x 70cm \/ none","offer_id":57010578882942,"sku":"MUS-CFPM-28X28","price":159.95,"currency_code":"GBP","in_stock":true},{"title":"Framed picture \/ XL: 90 x 90cm \/ none","offer_id":57010578915710,"sku":"MUS-CFPM-36X36","price":204.95,"currency_code":"GBP","in_stock":true},{"title":"Postcard \/ Standard: 6 x 4in \/ Single","offer_id":57010578948478,"sku":"GLOBAL-POST-MOH-6X4","price":1.95,"currency_code":"GBP","in_stock":true},{"title":"Postcard \/ Standard: 6 x 4in \/ 10-pack","offer_id":57010578981246,"sku":"GLOBAL-POST-MOH-6X4-10","price":14.95,"currency_code":"GBP","in_stock":true},{"title":"Postcard \/ Standard: 6 x 4in \/ 20-pack","offer_id":57010579014014,"sku":"GLOBAL-POST-MOH-6X4-20","price":24.95,"currency_code":"GBP","in_stock":true},{"title":"Postcard \/ Large: 7 x 5in \/ Single","offer_id":57010579046782,"sku":"GLOBAL-POST-MOH-7X5","price":2.95,"currency_code":"GBP","in_stock":true},{"title":"Postcard \/ Large: 7 x 5in \/ 10-pack","offer_id":57010579079550,"sku":"GLOBAL-POST-MOH-7X5-10","price":19.95,"currency_code":"GBP","in_stock":true},{"title":"Postcard \/ Large: 7 x 5in \/ 20-pack","offer_id":57010579112318,"sku":"GLOBAL-POST-MOH-7X5-20","price":29.95,"currency_code":"GBP","in_stock":true},{"title":"Greetings card \/ Standard: 6 x 4in \/ Single","offer_id":57010579145086,"sku":"GLOBAL-GRE-MOH-6X4-BLA","price":2.5,"currency_code":"GBP","in_stock":true},{"title":"Greetings card \/ Standard: 6 x 4in \/ 10-pack","offer_id":57010579177854,"sku":"GLOBAL-GRE-MOH-6X4-BLA-10","price":15.95,"currency_code":"GBP","in_stock":true},{"title":"Greetings card \/ Standard: 6 x 4in \/ 20-pack","offer_id":57010579210622,"sku":"GLOBAL-GRE-MOH-6X4-BLA-20","price":26.95,"currency_code":"GBP","in_stock":true},{"title":"Greetings card \/ Large: 7 x 5in \/ Single","offer_id":57010579243390,"sku":"GLOBAL-GRE-MOH-7X5-BLA","price":3.5,"currency_code":"GBP","in_stock":true},{"title":"Greetings card \/ Large: 7 x 5in \/ 10-pack","offer_id":57010579276158,"sku":"GLOBAL-GRE-MOH-7X5-BLA-10","price":19.95,"currency_code":"GBP","in_stock":true},{"title":"Greetings card \/ Large: 7 x 5in \/ 20-pack","offer_id":57010579308926,"sku":"GLOBAL-GRE-MOH-7X5-BLA-20","price":33.95,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/2785\/2654\/products\/f4767-001_c0cdbfd0-71f1-4a90-96d8-796cd1a1b57d.jpg?v=1527776193","url":"https:\/\/prints.rmg.co.uk\/products\/lodestone-f4767-001","provider":"Royal Museums Greenwich prints","version":"1.0","type":"link"}