▁in ▁a ▁cre amy ▁white ▁layer ▁which ▁was ▁mixed ▁in ▁with ▁the ▁l ichen ▁fung us . ▁ ▁A ▁sc anning ▁electron ▁micro graph ▁of ▁samples ▁taken ▁showed ▁that ▁the ▁cry st als ▁had ▁a ▁py ram idal ▁structure ▁with ▁both ▁cur ved ▁and ▁stri ated ▁faces . ▁ ▁The ▁size ▁of ▁these ▁cry st als ▁r anged ▁from ▁▁ 2 ▁to ▁ 5 ▁ μ m . ▁ ▁Syn thesis ▁and ▁re actions ▁▁ ▁Mag nes ium ▁ox al ate ▁can ▁by ▁synth es ized ▁by ▁combining ▁a ▁mag nes ium ▁salt ▁or ▁ion ▁with ▁an ▁ox al ate . ▁ ▁M g 2 ++ CO 2 − ▁→ ▁M g CO ▁A ▁specific ▁example ▁of ▁a ▁synth esis ▁would ▁be ▁mixing ▁M g ( NO 3 ) 2 ▁and ▁K OH ▁and ▁then ▁adding ▁that ▁solution ▁to ▁( CO O CH 3 ) 2 . ▁Mag nes ium ▁ox al ate ▁when ▁he ated ▁will ▁de compose . ▁ ▁First , ▁the ▁di h yd rate ▁will ▁de compose ▁at ▁ 1 5 0   ° C ▁into ▁the ▁an h yd r ous ▁form . ▁ ▁M g CO • 2 H 2 O ▁→ ▁M g CO ▁+ ▁ 2 H 2 O ▁ ▁With ▁additional ▁he ating ▁the ▁an h yd r ous ▁form ▁will ▁de compose ▁further ▁into ▁mag nes ium ▁ox ide ▁and ▁carbon ▁ox ides ▁between ▁ 4 2 0   ° C ▁and ▁ 6 2 0   ° C . ▁ ▁First ▁carbon