( 88r> ) 



3. Intergrowths of other minerals. 



In astrophj^llitelujaurites we mentioned the poicilitic intergrowth 

 of astroplijUite witli felspatoids. In schistose lujaurites from Tusschen- 

 komst (3311 which are very rich in aegirine, crystals of astrophyllite 

 which are allotriomorphic with regard to felspars and felspatoids, 

 enclose innumerable needles of aegirine with different orientation ; 

 the aegirine can fill up more than half of the crystal. 



Thus in these rocks astrophyllite is the latest product of crystal- 

 lization, whereas it is one of the first crystallized minerals in aegirine- 

 amphibolefoyaites from Wijdhoek (701), where its idiomorphic 

 crystals lie scattered in the other minerals. The eucolite mineral 

 which is strongly altered to catapleite, is idiomorphic in these rocks, 

 whereas in a lujaurite from Kruidfonlein (649) it is allotriomorphic 

 with regard to felspars and felspatoids, and encloses innumerable 

 small crystals of aegirine. 



In this rock eucolite is the latest product of crystallization just 

 as in the astrophyllitebearing aegirineamphibolefoyaites from Wijd- 

 hoek (701), where it has been formed simultaneously with aegirine- 

 spherolites, which are younger than all other minerals. 



In the molengraaffitebearing lujaurites from the southwestern, part 

 of Wijdhoek (701), crystals of a pectolite mineral occur, which are 

 crystallized in angular forms between the other minerals, and enclose 

 numerous needles of aegirine. Between crossed nicols the aegirine 

 contrasts against a strongly birefringent back-ground showing equal 

 optical orientation over a large distance whereas the connection 

 between different parts of one single crystal is often Droken. 



In a lujauriteporphyry from Wijdhoek (101) which is rich in pectolite, 

 this mineral is either jammed in angular form between the other 

 minerals, or it encloses poicilitically the felspatoids and aegirine of 

 the groundmass, whilst lath-shaped felspars occur in them with 

 idiomorphic forms. Especially with the felspatoids i1 is often interlaced 

 with sieve structure. In the same rock both the felspatoids are en- 

 closed by eucolite, and the sodalite principally is enclosed by the felspars. 



The crystallization of the pectolite already belongs to the pneu- 

 matolytic period in which the material for the growth of the minerals 

 was partly given by reabsorption of these minerals which had been 

 crystallized previously. According to this we see it accompanied by 

 abnormal analcime, spherical aegirine, albite and fluorspar. 



All that has been said above, tends to prove that the order of 

 succession of the crystallization is not constant in these rocks, and 



